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Zou Z, Wang Q, Wu X, Schultz RM, Xie W. Kick-starting the zygotic genome: licensors, specifiers, and beyond. EMBO Rep 2024:10.1038/s44319-024-00223-5. [PMID: 39160344 DOI: 10.1038/s44319-024-00223-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 06/14/2024] [Accepted: 07/24/2024] [Indexed: 08/21/2024] Open
Abstract
Zygotic genome activation (ZGA), the first transcription event following fertilization, kickstarts the embryonic program that takes over the control of early development from the maternal products. How ZGA occurs, especially in mammals, is poorly understood due to the limited amount of research materials. With the rapid development of single-cell and low-input technologies, remarkable progress made in the past decade has unveiled dramatic transitions of the epigenomes, transcriptomes, proteomes, and metabolomes associated with ZGA. Moreover, functional investigations are yielding insights into the key regulators of ZGA, among which two major classes of players are emerging: licensors and specifiers. Licensors would control the permission of transcription and its timing during ZGA. Accumulating evidence suggests that such licensors of ZGA include regulators of the transcription apparatus and nuclear gatekeepers. Specifiers would instruct the activation of specific genes during ZGA. These specifiers include key transcription factors present at this stage, often facilitated by epigenetic regulators. Based on data primarily from mammals but also results from other species, we discuss in this review how recent research sheds light on the molecular regulation of ZGA and its executors, including the licensors and specifiers.
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Affiliation(s)
- Zhuoning Zou
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Qiuyan Wang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Xi Wu
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, 100084, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences (PTN) Joint Graduate Program, Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
| | - Richard M Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, Davis, CA, USA
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, 100084, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
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2
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Siddiqui NU, Karaiskakis A, Goldman AL, Eagle WVI, Low TCH, Luo H, Smibert CA, Gavis ER, Lipshitz HD. Smaug regulates germ plasm assembly and primordial germ cell number in Drosophila embryos. SCIENCE ADVANCES 2024; 10:eadg7894. [PMID: 38608012 PMCID: PMC11014450 DOI: 10.1126/sciadv.adg7894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/12/2024] [Indexed: 04/14/2024]
Abstract
During Drosophila oogenesis, the Oskar (OSK) RNA binding protein (RBP) determines the amount of germ plasm that assembles at the posterior pole of the oocyte. Here, we identify mechanisms that subsequently regulate germ plasm assembly in the early embryo. We show that the Smaug (SMG) RBP is transported into the germ plasm of the early embryo where it accumulates in the germ granules. SMG binds to and represses translation of the osk messenger RNA (mRNA) as well as the bruno 1 (bru1) mRNA, which encodes an RBP that we show promotes germ plasm production. Loss of SMG or mutation of SMG's binding sites in the osk or bru1 mRNA results in excess translation of these transcripts in the germ plasm, accumulation of excess germ plasm, and budding of excess primordial germ cells (PGCs). Therefore, SMG triggers a posttranscriptional regulatory pathway that attenuates the amount of germ plasm in embryos to modulate the number of PGCs.
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Affiliation(s)
- Najeeb U. Siddiqui
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
- Program in Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Angelo Karaiskakis
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Aaron L. Goldman
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
- Program in Developmental and Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Whitby V. I. Eagle
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Timothy C. H. Low
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Hua Luo
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Craig A. Smibert
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Elizabeth R. Gavis
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Howard D. Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
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3
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Sumitha MK, Kalimuthu M, Aarthy M, Paramasivan R, Kumar A, Gupta B. In silico identification, characterization, and expression analysis of RNA recognition motif (RRM) containing RNA-binding proteins in Aedes aegypti. Parasitol Res 2023; 122:2847-2857. [PMID: 37735272 DOI: 10.1007/s00436-023-07969-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 09/04/2023] [Indexed: 09/23/2023]
Abstract
RNA-binding proteins (RBPs) are the proteins that bind RNAs and regulate their functioning. RBPs in mosquitoes are gaining attention due to their ability to bind flaviviruses and regulate their replication and transmission. Despite their relevance, RBPs in mosquitoes are not explored much. In this study, we screened the whole genome of Aedes aegypti, the primary vector of several pathogenic viruses, and identified the proteins containing RNA recognition motif (RRM), the most abundant protein domain in eukaryotes. Using several in silico strategies, a total of 135 RRM-containing RBPs were identified in Ae. aegypti. The proteins were characterized based on their available annotations and the sequence similarity with Drosophila melanogaster. Ae. aegypti RRM-containing RBPs included serine/arginine-rich (SR) proteins, polyadenylate-binding proteins (PABP), heteronuclear ribonucleoproteins (hnRNP), small nuclear ribonucleoproteins (snRNP), splicing factors, eukaryotic initiation factors, transformers, and nucleolysins. Phylogenetic analysis revealed that the proteins and the domain organization are conserved among Ae. aegypti, Bombyx mori, and Drosophila melanogaster. However, the gene length and the intron-exon organization varied across the insect species. Expression analysis of the genes encoding RBPs using publicly available RNA sequencing data for different developmental time points of the mosquito life cycle starting from the ovary and eggs up to the adults revealed stage-specific expression with several genes preferentially expressed in early embryonic stages and blood-fed female ovaries. This is the first database for the Ae. aegypti RBPs that can serve as the reference base for future investigations. Stage-specific genes can be further explored to determine their role in mosquito growth and development with a focus on developing novel mosquito control strategies.
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Affiliation(s)
- Melveettil Kishor Sumitha
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Mariapillai Kalimuthu
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Murali Aarthy
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Rajaiah Paramasivan
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Ashwani Kumar
- ICMR-Vector Control Research Centre (VCRC), Puducherry, India
| | - Bhavna Gupta
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India.
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4
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Harrison MM, Marsh AJ, Rushlow CA. Setting the stage for development: the maternal-to-zygotic transition in Drosophila. Genetics 2023; 225:iyad142. [PMID: 37616526 PMCID: PMC10550319 DOI: 10.1093/genetics/iyad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/18/2023] [Indexed: 08/26/2023] Open
Abstract
The zygote has a daunting task ahead of itself; it must develop from a single cell (fertilized egg) into a fully functioning adult with a multitude of different cell types. In the beginning, the zygote has help from its mother, in the form of gene products deposited into the egg, but eventually, it must rely on its own resources to proceed through development. The transfer of developmental control from the mother to the embryo is called the maternal-to-zygotic transition (MZT). All animals undergo this transition, which is defined by two main processes-the degradation of maternal RNAs and the synthesis of new RNAs from the zygote's own genome. Here, we review the regulation of the MZT in Drosophila, but given the broad conservation of this essential process, much of the regulation is shared among metazoans.
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Affiliation(s)
- Melissa M Harrison
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
| | - Audrey J Marsh
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706USA
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5
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Kubíková J, Ubartaitė G, Metz J, Jeske M. Structural basis for binding of Drosophila Smaug to the GPCR Smoothened and to the germline inducer Oskar. Proc Natl Acad Sci U S A 2023; 120:e2304385120. [PMID: 37523566 PMCID: PMC10410706 DOI: 10.1073/pnas.2304385120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/28/2023] [Indexed: 08/02/2023] Open
Abstract
Drosophila Smaug and its orthologs comprise a family of mRNA repressor proteins that exhibit various functions during animal development. Smaug proteins contain a characteristic RNA-binding sterile-α motif (SAM) domain and a conserved but uncharacterized N-terminal domain (NTD). Here, we resolved the crystal structure of the NTD of the human SAM domain-containing protein 4A (SAMD4A, a.k.a. Smaug1) to 1.6 Å resolution, which revealed its composition of a homodimerization D subdomain and a subdomain with similarity to a pseudo-HEAT-repeat analogous topology (PHAT) domain. Furthermore, we show that Drosophila Smaug directly interacts with the Drosophila germline inducer Oskar and with the Hedgehog signaling transducer Smoothened through its NTD. We determined the crystal structure of the NTD of Smaug in complex with a Smoothened α-helical peptide to 2.0 Å resolution. The peptide binds within a groove that is formed by both the D and PHAT subdomains. Structural modeling supported by experimental data suggested that an α-helix within the disordered region of Oskar binds to the NTD of Smaug in a mode similar to Smoothened. Together, our data uncover the NTD of Smaug as a peptide-binding domain.
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Affiliation(s)
- Jana Kubíková
- Biochemistry Center, Heidelberg University, Heidelberg69120, Germany
| | | | - Jutta Metz
- Biochemistry Center, Heidelberg University, Heidelberg69120, Germany
| | - Mandy Jeske
- Biochemistry Center, Heidelberg University, Heidelberg69120, Germany
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6
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David OG, Sanchez KM, Arce AV, Costa-da-Silva AL, Bellantuono AJ, DeGennaro M. Fertility decline in female mosquitoes is regulated by the orco olfactory co-receptor. iScience 2023; 26:106883. [PMID: 37275523 PMCID: PMC10239028 DOI: 10.1016/j.isci.2023.106883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/23/2023] [Accepted: 05/11/2023] [Indexed: 06/07/2023] Open
Abstract
Female Aedes aegypti mosquitoes undergo multiple rounds of reproduction, known as gonotrophic cycles. These cycles span the period from blood meal intake to oviposition. Understanding how reproductive success is maintained across gonotrophic cycles allows for the identification of molecular targets to reduce mosquito population growth. Odorant receptor co-receptor (orco) encodes a conserved insect-specific transmembrane ion channel that complexes with tuning odorant receptors (ORs) to form a functional olfactory receptor. orco expression has been identified in the male and female mosquito germline, but its role is unclear. We report an orco-dependent, maternal effect reduction in fertility after the first gonotrophic cycle. This phenotype was removed by CRISPR-Cas9 reversion of the orco mutant locus. Eggs deposited by orco mutant females are fertilized but the embryos reveal developmental defects, reduced hatching, and changes in ion channel signaling gene transcription. We present an unexpected role for an olfactory receptor pathway in mosquito reproduction.
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Affiliation(s)
- Olayinka G. David
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Kevin M. Sanchez
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Andrea V. Arce
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Andre Luis Costa-da-Silva
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Anthony J. Bellantuono
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Matthew DeGennaro
- Department of Biological Sciences & Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
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7
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Zhao Y, Zhai Y, Fu C, Shi L, Kong X, Li Q, Yu H, An X, Zhang S, Li Z. Transcription factor ELK1 regulates the expression of histone 3 lysine 9 to affect developmental potential of porcine preimplantation embryos. Theriogenology 2023; 206:170-180. [PMID: 37224706 DOI: 10.1016/j.theriogenology.2023.05.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/07/2023] [Accepted: 05/17/2023] [Indexed: 05/26/2023]
Abstract
A series of changes occur in the early embryo that are critical for subsequent development, and the pig is an excellent animal model of human disease, so understanding the regulatory mechanisms of early embryonic development in the pig is of very importance. To find key transcription factors regulating pig early embryonic development, we first profiled the transcriptome of pig early embryos, and confirmed that zygotic gene activation (ZGA) in porcine embryos starts from 4 cell stage. Subsequent enrichment analysis of up-regulated gene motifs during ZGA revealed that the transcription factor ELK1 ranked first. The expression pattern of ELK1 in porcine early embryos was analyzed by immunofluorescence staining and qPCR, and the results showed that the transcript level of ELK1 reached the highest at the 8 cell stage, while the protein level reached the highest at 4 cell stage. To further investigate the effect of ELK1 on early embryo development in pigs, we silenced ELK1 in zygotes and showed that ELK1 silencing significantly reduced cleavage rate, blastocyst rate as well as blastocyst quality. A significant decrease in the expression of the pluripotency gene Oct4 was also observed in blastocysts from the ELK1 silenced group by immunofluorescence staining. Silencing of ELK1 also resulted in decreased H3K9Ac modification and increased H3K9me3 modification at 4 cell stage. To investigate the effect of ELK1 on ZGA, we analyzed transcriptome changes in 4 cell embryos after ELK1 silencing by RNA seq, which revealed that ELK1 silencing resulted in significant differences in the expression of a total of 1953 genes at the 4 cell stage compared with their normal counterparts, including 1106 genes that were significantly upregulated and 847 genes that were significantly downregulated. Through GO and KEGG enrichment, we found that the functions and pathways of down-regulated genes were concentrated in protein synthesis, processing, cell cycle regulation, etc., while the functions of up-regulated genes were focused on aerobic respiration process. In conclusion, this study demonstrates that the transcription factor ELK1 plays an important role in regulation of preimplantation embryo development of pigs and deficiency of ELK1 leads to abnormal epigenetic reprogramming as well as zygotic genome activation, thus adversely affecting embryonic development. This study will provide important reference for the regulation of transcription factors in porcine embryo development.
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Affiliation(s)
- Yuanshen Zhao
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Yanhui Zhai
- Shenzhen Key Laboratory of Fertility Regulation, Center of Assisted Reproduction and Embryology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, Guangdong, 518053, China
| | - Cong Fu
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Lijing Shi
- College of Animal Science, Jilin University, Changchun, Jilin, 130062, China
| | - Xiangjie Kong
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Qi Li
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Hao Yu
- College of Animal Science, Jilin University, Changchun, Jilin, 130062, China
| | - Xinglan An
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Sheng Zhang
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China
| | - Ziyi Li
- Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, First Hospital of Jilin University, Changchun, Jilin, 130021, China.
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8
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Riemondy K, Henriksen JC, Rissland OS. Intron dynamics reveal principles of gene regulation during the maternal-to-zygotic transition. RNA (NEW YORK, N.Y.) 2023; 29:596-608. [PMID: 36764816 PMCID: PMC10158999 DOI: 10.1261/rna.079168.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 01/29/2023] [Indexed: 05/06/2023]
Abstract
The maternal-to-zygotic transition (MZT) is a conserved embryonic process in animals where developmental control shifts from the maternal to zygotic genome. A key step in this transition is zygotic transcription, and deciphering the MZT requires classifying newly transcribed genes. However, due to current technological limitations, this starting point remains a challenge for studying many species. Here, we present an alternative approach that characterizes transcriptome changes based solely on RNA-seq data. By combining intron-mapping reads and transcript-level quantification, we characterized transcriptome dynamics during the Drosophila melanogaster MZT. Our approach provides an accessible platform to investigate transcriptome dynamics that can be applied to the MZT in nonmodel organisms. In addition to classifying zygotically transcribed genes, our analysis revealed that over 300 genes express different maternal and zygotic transcript isoforms due to alternative splicing, polyadenylation, and promoter usage. The vast majority of these zygotic isoforms have the potential to be subject to different regulatory control, and over two-thirds encode different proteins. Thus, our analysis reveals an additional layer of regulation during the MZT, where new zygotic transcripts can generate additional proteome diversity.
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Affiliation(s)
- Kent Riemondy
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Jesslyn C Henriksen
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Olivia S Rissland
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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9
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Hakes AC, Gavis ER. Plasticity of Drosophila germ granules during germ cell development. PLoS Biol 2023; 21:e3002069. [PMID: 37053289 PMCID: PMC10128949 DOI: 10.1371/journal.pbio.3002069] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/25/2023] [Accepted: 03/07/2023] [Indexed: 04/15/2023] Open
Abstract
Compartmentalization of RNAs and proteins into membraneless structures called granules is a ubiquitous mechanism for organizing and regulating cohorts of RNAs. Germ granules are ribonucleoprotein (RNP) assemblies required for germline development across the animal kingdom, but their regulatory roles in germ cells are not fully understood. We show that after germ cell specification, Drosophila germ granules enlarge through fusion and this growth is accompanied by a shift in function. Whereas germ granules initially protect their constituent mRNAs from degradation, they subsequently target a subset of these mRNAs for degradation while maintaining protection of others. This functional shift occurs through the recruitment of decapping and degradation factors to the germ granules, which is promoted by decapping activators and renders these structures P body-like. Disrupting either the mRNA protection or degradation function results in germ cell migration defects. Our findings reveal plasticity in germ granule function that allows them to be repurposed at different stages of development to ensure population of the gonad by germ cells. Additionally, these results reveal an unexpected level of functional complexity whereby constituent RNAs within the same granule type can be differentially regulated.
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Affiliation(s)
- Anna C Hakes
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
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10
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Siddiqui NU, Karaiskakis A, Goldman AL, Eagle WV, Smibert CA, Gavis ER, Lipshitz HD. Smaug regulates germ plasm synthesis and primordial germ cell number in Drosophila embryos by repressing the oskar and bruno 1 mRNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530189. [PMID: 36909513 PMCID: PMC10002672 DOI: 10.1101/2023.02.27.530189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
During Drosophila oogenesis, the Oskar (OSK) RNA-binding protein (RBP) determines the amount of germ plasm that assembles at the posterior pole of the oocyte. Here we identify the mechanisms that regulate the osk mRNA in the early embryo. We show that the Smaug (SMG) RBP is transported into the germ plasm of the early embryo where it accumulates in the germ granules. SMG binds to and represses translation of the osk mRNA itself as well as the bruno 1 (bru1) mRNA, which encodes an RBP that we show promotes germ plasm production. Loss of SMG or mutation of SMG's binding sites in the osk or bru1 mRNAs results in ectopic translation of these transcripts in the germ plasm and excess PGCs. SMG therefore triggers a post-transcriptional regulatory pathway that attenuates germ plasm synthesis in embryos, thus modulating the number of PGCs.
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Affiliation(s)
- Najeeb U. Siddiqui
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
- Program in Developmental & Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Angelo Karaiskakis
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Aaron L. Goldman
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
- Program in Developmental & Stem Cell Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Whitby V.I. Eagle
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Craig A. Smibert
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
| | - Elizabeth R. Gavis
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - Howard D. Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada M5G 1M1
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11
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Shen W, Gong B, Xing C, Zhang L, Sun J, Chen Y, Yang C, Yan L, Chen L, Yao L, Li G, Deng H, Wu X, Meng A. Comprehensive maturity of nuclear pore complexes regulates zygotic genome activation. Cell 2022; 185:4954-4970.e20. [PMID: 36493774 DOI: 10.1016/j.cell.2022.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/23/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022]
Abstract
Nuclear pore complexes (NPCs) are channels for nucleocytoplasmic transport of proteins and RNAs. However, it remains unclear whether composition, structure, and permeability of NPCs dynamically change during the cleavage period of vertebrate embryos and affect embryonic development. Here, we report that the comprehensive NPC maturity (CNM) controls the onset of zygotic genome activation (ZGA) during zebrafish early embryogenesis. We show that more nucleoporin proteins are recruited to and assembled into NPCs with development, resulting in progressive increase of NPCs in size and complexity. Maternal transcription factors (TFs) transport into nuclei more efficiently with increasing CNM. Deficiency or dysfunction of Nup133 or Ahctf1/Elys impairs NPC assembly, maternal TFs nuclear transport, and ZGA onset, while nup133 overexpression promotes these processes. Therefore, CNM may act as a molecular timer for ZGA by controlling nuclear transport of maternal TFs that reach nuclear concentration thresholds at a given time to initiate ZGA.
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Affiliation(s)
- Weimin Shen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bo Gong
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Cencan Xing
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lin Zhang
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiawei Sun
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuling Chen
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Changmei Yang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lu Yan
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Luxi Chen
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Likun Yao
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guangyuan Li
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaotong Wu
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Anming Meng
- Laboratory of Molecular Developmental Biology, State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China; Developmental Diseases and Cancer Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China; Laboratory of Stem Cell Regulation, Guangzhou Laboratory, Guangzhou 510320, China.
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12
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Thukral S, Kaity B, Mitra D, Dey B, Dey P, Uttekar B, Mitra MK, Nandi A, Rikhy R. Pseudocleavage furrows restrict plasma membrane-associated PH domain in syncytial Drosophila embryos. Biophys J 2022; 121:2419-2435. [PMID: 35591789 DOI: 10.1016/j.bpj.2022.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/13/2022] [Accepted: 05/13/2022] [Indexed: 11/02/2022] Open
Abstract
Syncytial cells contain multiple nuclei and have local distribution and function of cellular components despite being synthesized in a common cytoplasm. The syncytial Drosophila blastoderm embryo shows reduced spread of organelle and plasma membrane-associated proteins between adjacent nucleo-cytoplasmic domains. Anchoring to the cytoarchitecture within a nucleo-cytoplasmic domain is likely to decrease the spread of molecules; however, its role in restricting this spread has not been assessed. In order to analyze the cellular mechanisms that regulate the rate of spread of plasma membrane-associated molecules in the syncytial Drosophila embryos, we express a pleckstrin homology (PH) domain in a localized manner at the anterior of the embryo by tagging it with the bicoid mRNA localization signal. Anteriorly expressed PH-domain forms an exponential gradient in the anteroposterior axis with a longer length scale as compared to Bicoid. Using a combination of experiments and theoretical modeling, we find that the characteristic distribution and length scale emerge due to plasma membrane sequestration and restriction within an energid. Loss of plasma membrane remodeling to form pseudocleavage furrows shows an enhanced spread of PH-domain but not Bicoid. Modeling analysis suggests that the enhanced spread of the PH-domain occurs due to the increased spread of the cytoplasmic population of the PH-domain in pseudocleavage furrow mutants. Our analysis of cytoarchitecture interaction in regulating plasma membrane protein distribution and constraining its spread has implications on the mechanisms of spread of various molecules such as morphogens in syncytial cells.
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Affiliation(s)
- Sameer Thukral
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Bivash Kaity
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Debasmita Mitra
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Bipasha Dey
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Pampa Dey
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Bhavin Uttekar
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Mithun K Mitra
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Amitabha Nandi
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.
| | - Richa Rikhy
- Biology, Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune, 411008, India.
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13
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The embryonic transcriptome of Parhyale hawaiensis reveals different dynamics of microRNAs and mRNAs during the maternal-zygotic transition. Sci Rep 2022; 12:174. [PMID: 34996916 PMCID: PMC8741983 DOI: 10.1038/s41598-021-03642-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/09/2021] [Indexed: 11/18/2022] Open
Abstract
Parhyale hawaiensis has emerged as the crustacean model of choice due to its tractability, ease of imaging, sequenced genome, and development of CRISPR/Cas9 genome editing tools. However, transcriptomic datasets spanning embryonic development are lacking, and there is almost no annotation of non-protein-coding RNAs, including microRNAs. We have sequenced microRNAs, together with mRNAs and long non-coding RNAs, in Parhyale using paired size-selected RNA-seq libraries at seven time-points covering important transitions in embryonic development. Focussing on microRNAs, we annotate 175 loci in Parhyale, 88 of which have no known homologs. We use these data to annotate the microRNAome of 37 crustacean genomes, and suggest a core crustacean microRNA set of around 61 sequence families. We examine the dynamic expression of microRNAs and mRNAs during the maternal-zygotic transition. Our data suggest that zygotic genome activation occurs in two waves in Parhyale with microRNAs transcribed almost exclusively in the second wave. Contrary to findings in other arthropods, we do not predict a general role for microRNAs in clearing maternal transcripts. These data significantly expand the available transcriptomics resources for Parhyale, and facilitate its use as a model organism for the study of small RNAs in processes ranging from embryonic development to regeneration.
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14
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Cao WX, Karaiskakis A, Lin S, Angers S, Lipshitz HD. The F-box protein Bard (CG14317) targets the Smaug RNA-binding protein for destruction during the Drosophila maternal-to-zygotic transition. Genetics 2022; 220:iyab177. [PMID: 34757425 PMCID: PMC8733446 DOI: 10.1093/genetics/iyab177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/11/2021] [Indexed: 01/12/2023] Open
Abstract
During the maternal-to-zygotic transition (MZT), which encompasses the earliest stages of animal embryogenesis, a subset of maternally supplied gene products is cleared, thus permitting activation of zygotic gene expression. In the Drosophila melanogaster embryo, the RNA-binding protein Smaug (SMG) plays an essential role in progression through the MZT by translationally repressing and destabilizing a large number of maternal mRNAs. The SMG protein itself is rapidly cleared at the end of the MZT by a Skp/Cullin/F-box (SCF) E3-ligase complex. Clearance of SMG requires zygotic transcription and is required for an orderly MZT. Here, we show that an F-box protein, which we name Bard (encoded by CG14317), is required for degradation of SMG. Bard is expressed zygotically and physically interacts with SMG at the end of the MZT, coincident with binding of the maternal SCF proteins, SkpA and Cullin1, and with degradation of SMG. shRNA-mediated knock-down of Bard or deletion of the bard gene in the early embryo results in stabilization of SMG protein, a phenotype that is rescued by transgenes expressing Bard. Bard thus times the clearance of SMG at the end of the MZT.
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Affiliation(s)
- Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Angelo Karaiskakis
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sichun Lin
- Department of Pharmaceutical Sciences & Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences & Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
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15
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Lo Furno E, Busseau I, Aze A, Lorenzi C, Saghira C, Danzi MC, Zuchner S, Maiorano D. Translesion DNA synthesis-driven mutagenesis in very early embryogenesis of fast cleaving embryos. Nucleic Acids Res 2021; 50:885-898. [PMID: 34939656 PMCID: PMC8789082 DOI: 10.1093/nar/gkab1223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/22/2021] [Accepted: 12/22/2021] [Indexed: 11/19/2022] Open
Abstract
In early embryogenesis of fast cleaving embryos, DNA synthesis is short and surveillance mechanisms preserving genome integrity are inefficient, implying the possible generation of mutations. We have analyzed mutagenesis in Xenopus laevis and Drosophila melanogaster early embryos. We report the occurrence of a high mutation rate in Xenopus and show that it is dependent upon the translesion DNA synthesis (TLS) master regulator Rad18. Unexpectedly, we observed a homology-directed repair contribution of Rad18 in reducing the mutation load. Genetic invalidation of TLS in the pre-blastoderm Drosophila embryo resulted in reduction of both the hatching rate and single-nucleotide variations on pericentromeric heterochromatin in adult flies. Altogether, these findings indicate that during very early Xenopus and Drosophila embryos TLS strongly contributes to the high mutation rate. This may constitute a previously unforeseen source of genetic diversity contributing to the polymorphisms of each individual with implications for genome evolution and species adaptation.
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Affiliation(s)
- Elena Lo Furno
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Isabelle Busseau
- Systemic Impact of Small Regulatory RNAs Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Antoine Aze
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Claudio Lorenzi
- Machine Learning and Gene Regulation Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
| | - Cima Saghira
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Matt C Danzi
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Stephan Zuchner
- Department of Human Genetics, Hussman Institute for Human Genomics, University of Miami, Miami, FL 33136, USA
| | - Domenico Maiorano
- Genome Surveillance and Stability Laboratory, Institut de Génétique Humaine, Université de Montpellier, CNRS-UMR9002, 34000 Montpellier, France
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16
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Chille E, Strand E, Neder M, Schmidt V, Sherman M, Mass T, Putnam H. Developmental series of gene expression clarifies maternal mRNA provisioning and maternal-to-zygotic transition in a reef-building coral. BMC Genomics 2021; 22:815. [PMID: 34763678 PMCID: PMC8588723 DOI: 10.1186/s12864-021-08114-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Maternal mRNA provisioning of oocytes regulates early embryogenesis. Maternal transcripts are degraded as zygotic genome activation (ZGA) intensifies, a phenomenon known as the maternal-to-zygotic transition (MZT). Here, we examine gene expression over nine developmental stages in the Pacific rice coral, Montipora capitata, from eggs and embryos at 1, 4, 9, 14, 22, and 36 h-post-fertilization (hpf), as well as swimming larvae (9d), and adult colonies. RESULTS Weighted Gene Coexpression Network Analysis revealed four expression peaks, identifying the maternal complement, two waves of the MZT, and adult expression. Gene ontology enrichment revealed maternal mRNAs are dominated by cell division, methylation, biosynthesis, metabolism, and protein/RNA processing and transport functions. The first MZT wave occurs from ~4-14 hpf and is enriched in terms related to biosynthesis, methylation, cell division, and transcription. In contrast, functional enrichment in the second MZT wave, or ZGA, from 22 hpf-9dpf, includes ion/peptide transport and cell signaling. Finally, adult expression is enriched for functions related to signaling, metabolism, and ion/peptide transport. Our proposed MZT timing is further supported by expression of enzymes involved in zygotic transcriptional repression (Kaiso) and activation (Sox2), which peak at 14 hpf and 22 hpf, respectively. Further, DNA methylation writing (DNMT3a) and removing (TET1) enzymes peak and remain stable past ~4 hpf, suggesting that methylome programming occurs before 4 hpf. CONCLUSIONS Our high-resolution insight into the coral maternal mRNA and MZT provides essential baseline information to understand parental carryover effects and the sensitivity of developmental success under increasing environmental stress.
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Affiliation(s)
- Erin Chille
- Department of Biological Sciences, University of Rhode Island, Rhode Island, USA.
| | - Emma Strand
- Department of Biological Sciences, University of Rhode Island, Rhode Island, USA
| | - Mayaan Neder
- Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
- The Interuniversity Institute of Marine Science, 88103, Eilat, Israel
| | | | - Madeleine Sherman
- Department of Biological Sciences, University of Rhode Island, Rhode Island, USA
| | - Tali Mass
- Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Hollie Putnam
- Department of Biological Sciences, University of Rhode Island, Rhode Island, USA
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17
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Hemolymph Ecdysteroid Titer Affects Maternal mRNAs during Bombyx mori Oogenesis. INSECTS 2021; 12:insects12110969. [PMID: 34821770 PMCID: PMC8622876 DOI: 10.3390/insects12110969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 01/02/2023]
Abstract
Simple Summary Both maternal genes and ecdysteroids play important roles during embryonic development. In this study, we aimed to characterize the dynamic landscape of maternal mRNAs and the relationship between maternal genes and ecdysteroids during silkworm oogenesis. For the first time, we determined the start of the accumulation of maternal mRNAs in the ovary at the wandering stage during the larval period. We detected the developmental expression profiles of each gene in the ovary or ovariole. We finally confirmed the role of 20-hydroxyecdysone in regulating maternal gene expression. Taken together, our findings expand the understanding of insect oogenesis and provide a perspective on the embryonic development of the silkworm. Abstract Silkworm larval–pupal metamorphosis and the first half of pupal–adult development occur during oogenesis from previtellogenesis to vitellogenesis and include two peaks of the hemolymph ecdysteroid titer. Moreover, a rise in 20-hydroxyecdysone titer in early pupae can trigger the first major transition from previtellogenesis to vitellogenesis in silkworm oogenesis. In this study, we first investigated the expression patterns of 66 maternal genes in the ovary at the wandering stage. We then examined the developmental expression profiles in six time-series samples of ovaries or ovarioles by reverse transcription–quantitative PCR. We found that the transcripts of 22 maternal genes were regulated by 20-hydroxyecdysone in the isolated abdomens of the pupae following a single injection of 20-hydroxyecdysone. This study is the first to determine the relationship between 20-hydroxyecdysone and maternal genes during silkworm oogenesis. These findings provide a basis for further research into the embryonic development of Bombyx mori.
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18
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Su R, Fan LH, Cao C, Wang L, Du Z, Cai Z, Ouyang YC, Wang Y, Zhou Q, Wu L, Zhang N, Zhu X, Lei WL, Zhao H, Tian Y, He S, Wong CCL, Sun QY, Xue Y. Global profiling of RNA-binding protein target sites by LACE-seq. Nat Cell Biol 2021; 23:664-675. [PMID: 34108658 DOI: 10.1038/s41556-021-00696-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/07/2021] [Indexed: 02/05/2023]
Abstract
RNA-binding proteins (RBPs) have essential functions during germline and early embryo development. However, current methods are unable to identify the in vivo targets of a RBP in these low-abundance cells. Here, by coupling RBP-mediated reverse transcription termination with linear amplification of complementary DNA ends and sequencing, we present the LACE-seq method for identifying RBP-regulated RNA networks at or near the single-oocyte level. We determined the binding sites and regulatory mechanisms for several RBPs, including Argonaute 2 (Ago2), Mili, Ddx4 and Ptbp1, in mature mouse oocytes. Unexpectedly, transcriptomics and proteomics analysis of Ago2-/- oocytes revealed that Ago2 interacts with endogenous small interfering RNAs (endo-siRNAs) to repress mRNA translation globally. Furthermore, the Ago2 and endo-siRNA complexes fine-tune the transcriptome by slicing long terminal repeat retrotransposon-derived chimeric transcripts. The precise mapping of RBP-binding sites in low-input cells opens the door to studying the roles of RBPs in embryonic development and reproductive diseases.
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Affiliation(s)
- Ruibao Su
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li-Hua Fan
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Changchang Cao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Lei Wang
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, Xinyang Normal University, Xinyang, China
| | - Zongchang Du
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhaokui Cai
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ying-Chun Ouyang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yue Wang
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qian Zhou
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ligang Wu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Nan Zhang
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Beijing, China
| | - Xiaoxiao Zhu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wen-Long Lei
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Hailian Zhao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yong Tian
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shunmin He
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Catherine C L Wong
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Beijing, China. .,School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China. .,Peking University First Hospital, Beijing, China.
| | - Qing-Yuan Sun
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China. .,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
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19
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Cao WX, Kabelitz S, Gupta M, Yeung E, Lin S, Rammelt C, Ihling C, Pekovic F, Low TCH, Siddiqui NU, Cheng MHK, Angers S, Smibert CA, Wühr M, Wahle E, Lipshitz HD. Precise Temporal Regulation of Post-transcriptional Repressors Is Required for an Orderly Drosophila Maternal-to-Zygotic Transition. Cell Rep 2021; 31:107783. [PMID: 32579915 PMCID: PMC7372737 DOI: 10.1016/j.celrep.2020.107783] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/06/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
In animal embryos, the maternal-to-zygotic transition (MZT) hands developmental control from maternal to zygotic gene products. We show that the maternal proteome represents more than half of the protein-coding capacity of Drosophila melanogaster’s genome, and that 2% of this proteome is rapidly degraded during the MZT. Cleared proteins include the post-transcriptional repressors Cup, Trailer hitch (TRAL), Maternal expression at 31B (ME31B), and Smaug (SMG). Although the ubiquitin-proteasome system is necessary for clearance of these repressors, distinct E3 ligase complexes target them: the C-terminal to Lis1 Homology (CTLH) complex targets Cup, TRAL, and ME31B for degradation early in the MZT and the Skp/Cullin/F-box-containing (SCF) complex targets SMG at the end of the MZT. Deleting the C-terminal 233 amino acids of SMG abrogates F-box protein interaction and confers immunity to degradation. Persistent SMG downregulates zygotic re-expression of mRNAs whose maternal contribution is degraded by SMG. Thus, clearance of SMG permits an orderly MZT. Cao et al. show that 2% of the proteome is degraded in early Drosophila embryos, including a repressive ribonucleoprotein complex. Two E3 ubiquitin ligases separately act on distinct components of this complex to phase their clearance. Failure to degrade a key component, the Smaug RNA-binding protein, disrupts an orderly maternal-to-zygotic transition.
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Affiliation(s)
- Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sarah Kabelitz
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Meera Gupta
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Eyan Yeung
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Sichun Lin
- Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada
| | - Christiane Rammelt
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Christian Ihling
- Institute of Pharmacy and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Filip Pekovic
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Timothy C H Low
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Najeeb U Siddiqui
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Matthew H K Cheng
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Martin Wühr
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany.
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
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20
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Argonaute 2 is a key regulator of maternal mRNA degradation in mouse early embryos. Cell Death Discov 2020; 6:133. [PMID: 33298889 PMCID: PMC7691497 DOI: 10.1038/s41420-020-00368-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/06/2020] [Accepted: 11/02/2020] [Indexed: 11/16/2022] Open
Abstract
In mammalian early embryos, the transition from maternal to embryonic control of gene expression requires timely degradation of a subset of maternal mRNAs (MRD). Recently, zygotic genome activation (ZGA)-dependent MRD has been characterized in mouse 2-cell embryo. However, in early embryos, the dynamics of MRD is still poorly understood, and the maternal factor-mediated MRD before and along with ZGA has not been investigated. Argonaute 2 (Ago2) is highly expressed in mouse oocyte and early embryos. In this study, we showed that Ago2-dependent degradation involving RNA interference (RNAi) and RNA activation (RNAa) pathways contributes to the decay of over half of the maternal mRNAs in mouse early embryos. We demonstrated that AGO2 guided by endogenous small interfering RNAs (endosiRNAs), generated from double-stranded RNAs (dsRNAs) formed by maternal mRNAs with their complementary long noncoding RNAs (CMR-lncRNAs), could target maternal mRNAs and cooperate with P-bodies to promote MRD. In addition, we also showed that AGO2 may interact with small activating RNAs (saRNAs) to activate Yap1 and Tead4, triggering ZGA-dependent MRD. Thus, Ago2-dependent degradation is required for timely elimination of subgroups of maternal mRNAs and facilitates the transition between developmental states.
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21
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Sha QQ, Zheng W, Wu YW, Li S, Guo L, Zhang S, Lin G, Ou XH, Fan HY. Dynamics and clinical relevance of maternal mRNA clearance during the oocyte-to-embryo transition in humans. Nat Commun 2020; 11:4917. [PMID: 33004802 PMCID: PMC7530992 DOI: 10.1038/s41467-020-18680-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 09/03/2020] [Indexed: 01/29/2023] Open
Abstract
Maternal mRNA clearance is an essential process that occurs during maternal-to-zygotic transition (MZT). However, the dynamics, functional importance, and pathological relevance of maternal mRNA decay in human preimplantation embryos have not yet been analyzed. Here we report the zygotic genome activation (ZGA)-dependent and -independent maternal mRNA clearance processes during human MZT and demonstrate that subgroups of human maternal transcripts are sequentially removed by maternal (M)- and zygotic (Z)-decay pathways before and after ZGA. Key factors regulating M-decay and Z-decay pathways in mouse have similar expression pattern during human MZT, suggesting that YAP1-TEAD4 transcription activators, TUT4/7-mediated mRNA 3ʹ-oligouridylation, and BTG4/CCR4-NOT-induced mRNA deadenylation may also be involved in the regulation of human maternal mRNA stability. Decreased expression of these factors and abnormal accumulation of maternal transcripts are observed in the development-arrested embryos of patients who seek assisted reproduction. Defects of M-decay and Z-decay are detected with high incidence in embryos that are arrested at the zygote and 8-cell stages, respectively. In addition, M-decay is not found to be affected by maternal TUBB8 mutations, although these mutations cause meiotic cell division defects and zygotic arrest, which indicates that mRNA decay is regulated independent of meiotic spindle assembly. Considering the correlations between maternal mRNA decay defects and early developmental arrest of in vitro fertilized human embryos, M-decay and Z-decay pathway activities may contribute to the developmental potential of human preimplantation embryos. How maternal RNA clearance is regulated in human preimplantation embryos is unclear. Here, the authors show there is a potential correlation between maternal mRNA decay defects and early developmental arrest from in vitro fertilized human embryos, suggesting that M-decay and Z-decay pathways may regulate such early development.
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Affiliation(s)
- Qian-Qian Sha
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317, Guangzhou, China
| | - Wei Zheng
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-XIANGYA, 410008, Changsha, China.,College of Life Science, Hunan Normal University, 410006, Changsha, China
| | - Yun-Wen Wu
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China
| | - Sen Li
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317, Guangzhou, China
| | - Lei Guo
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317, Guangzhou, China
| | - Shuoping Zhang
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-XIANGYA, 410008, Changsha, China
| | - Ge Lin
- Clinical Research Center for Reproduction and Genetics in Hunan Province, Reproductive and Genetic Hospital of CITIC-XIANGYA, 410008, Changsha, China. .,Laboratory of Reproductive and Stem Cell Engineering, Key Laboratory of National Health and Family Planning Commission, Central South University, 410008, Changsha, China.
| | - Xiang-Hong Ou
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, 510317, Guangzhou, China.
| | - Heng-Yu Fan
- Life Sciences Institute, Zhejiang University, 310058, Hangzhou, China.
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22
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Sha QQ, Zhang J, Fan HY. A story of birth and death: mRNA translation and clearance at the onset of maternal-to-zygotic transition in mammals†. Biol Reprod 2020; 101:579-590. [PMID: 30715134 DOI: 10.1093/biolre/ioz012] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/18/2019] [Accepted: 01/30/2019] [Indexed: 01/01/2023] Open
Abstract
In mammals, maternal-to-zygotic transition (MZT), or oocyte-to-embryo transition, begins with oocyte meiotic resumption due to the sequential translational activation and destabilization of dormant maternal transcripts stored in the ooplasm. It then continues with the elimination of maternal transcripts during oocyte maturation and fertilization and ends with the full transcriptional activation of the zygotic genome during embryonic development. A hallmark of MZT in mammals is its reliance on translation and the utilization of stored RNAs and proteins, rather than de novo transcription of genes, to sustain meiotic maturation and early development. Impaired maternal mRNA clearance at the onset of MZT prevents zygotic genome activation and causes early arrest of developing embryos. In this review, we discuss recent advances in our knowledge of the mechanisms whereby mRNA translation and degradation are controlled by cytoplasmic polyadenylation and deadenylation which set up the competence of maturing oocyte to accomplish MZT. The emphasis of this review is on the mouse as a model organism for mammals and BTG4 as a licensing factor of MZT under the translational control of the MAPK cascade.
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Affiliation(s)
- Qian-Qian Sha
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Jue Zhang
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Heng-Yu Fan
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China.,Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province; Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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23
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Zavortink M, Rutt LN, Dzitoyeva S, Henriksen JC, Barrington C, Bilodeau DY, Wang M, Chen XXL, Rissland OS. The E2 Marie Kondo and the CTLH E3 ligase clear deposited RNA binding proteins during the maternal-to-zygotic transition. eLife 2020; 9:53889. [PMID: 32573431 PMCID: PMC7384856 DOI: 10.7554/elife.53889] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 06/23/2020] [Indexed: 12/12/2022] Open
Abstract
The maternal-to-zygotic transition (MZT) is a conserved step in animal development, where control is passed from the maternal to the zygotic genome. Although the MZT is typically considered from its impact on the transcriptome, we previously found that three maternally deposited Drosophila RNA-binding proteins (ME31B, Trailer Hitch [TRAL], and Cup) are also cleared during the MZT by unknown mechanisms. Here, we show that these proteins are degraded by the ubiquitin-proteasome system. Marie Kondo, an E2 conjugating enzyme, and the E3 CTLH ligase are required for the destruction of ME31B, TRAL, and Cup. Structure modeling of the Drosophila CTLH complex suggests that substrate recognition is different than orthologous complexes. Despite occurring hours earlier, egg activation mediates clearance of these proteins through the Pan Gu kinase, which stimulates translation of Kdo mRNA. Clearance of the maternal protein dowry thus appears to be a coordinated, but as-yet underappreciated, aspect of the MZT. Bestselling author and organizing consultant Marie Kondo has helped people around the world declutter their homes by getting rid of physical items that do not bring them joy. Keeping the crowded environment inside a living cell organized also requires work and involves removing molecules that are no longer needed. A fertilized egg cell, for example, contains molecules from the mother that regulate the initial stages as it develops into an embryo. Later on, the embryo takes control of its own development by destroying these inherited molecules and switches to making its own instead. This process is called the maternal-to-zygotic transition. The molecules passed from the mother to the egg cell include proteins and messenger RNAs (molecules that include the coded instructions to make new proteins). Previous research has begun to reveal how the embryo destroys the mRNAs it inherits from its mother and how it starts to make its own. Yet almost nothing is known about how an embryo gets rid of its mother’s proteins. To address this question, Zavortink, Rutt, Dzitoyeva et al. used an approach known as an RNA interference screen to identify factors required to destroy three maternal proteins in fruit fly embryos. The experiments helped identify one enzyme that worked together with another larger enzyme complex to destroy the maternal proteins. This enzyme belongs to a class of enzymes known as ubiquitin-conjugating enzymes (or E2 enzymes) and it was given the name “Kdo”, short for “Marie Kondo”. Further experiments showed that the mRNAs that code for the Kdo enzyme were present in unfertilized eggs, but in a repressed state that prevented the eggs from making the enzyme. Once an egg started to develop into an embryo, these mRNAs became active and the embryo started to make Kdo enzymes. This led to the three maternal proteins being destroyed during the maternal-to-zygotic transition. These findings reveal a new pathway that regulates the destruction of maternal proteins as the embryo develops. The next challenge will be identifying other maternal proteins that do not “spark joy” and understanding the role their destruction plays in the earliest events of embryonic development.
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Affiliation(s)
| | - Lauren N Rutt
- University of Colorado School of Medicine, Aurora, United States
| | | | | | - Chloe Barrington
- University of Colorado School of Medicine, Aurora, United States
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24
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Zhao LW, Zhu YZ, Chen H, Wu YW, Pi SB, Chen L, Shen L, Fan HY. PABPN1L mediates cytoplasmic mRNA decay as a placeholder during the maternal-to-zygotic transition. EMBO Rep 2020; 21:e49956. [PMID: 32558204 DOI: 10.15252/embr.201949956] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 12/14/2022] Open
Abstract
Maternal mRNA degradation is a critical event of the maternal-to-zygotic transition (MZT) that determines the developmental potential of early embryos. Nuclear Poly(A)-binding proteins (PABPNs) are extensively involved in mRNA post-transcriptional regulation, but their function in the MZT has not been investigated. In this study, we find that the maternally expressed PABPN1-like (PABPN1L), rather than its ubiquitously expressed homolog PABPN1, acts as an mRNA-binding adapter of the mammalian MZT licensing factor BTG4, which mediates maternal mRNA clearance. Female Pabpn1l null mice produce morphologically normal oocytes but are infertile owing to early developmental arrest of the resultant embryos at the 1- to 2-cell stage. Deletion of Pabpn1l impairs the deadenylation and degradation of a subset of BTG4-targeted maternal mRNAs during the MZT. In addition to recruiting BTG4 to the mRNA 3'-poly(A) tails, PABPN1L is also required for BTG4 protein accumulation in maturing oocytes by protecting BTG4 from SCF-βTrCP1 E3 ubiquitin ligase-mediated polyubiquitination and degradation. This study highlights a noncanonical cytoplasmic function of nuclear poly(A)-binding protein in mRNA turnover, as well as its physiological importance during the MZT.
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Affiliation(s)
- Long-Wen Zhao
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Ye-Zhang Zhu
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Hao Chen
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Yun-Wen Wu
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Shuai-Bo Pi
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Lu Chen
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Li Shen
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Heng-Yu Fan
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China.,Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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25
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Peng W, Yu S, Handler AM, Zhang H. Transcriptome Analysis of the Oriental Fruit Fly Bactrocera dorsalis Early Embryos. INSECTS 2020; 11:insects11050323. [PMID: 32456171 PMCID: PMC7290859 DOI: 10.3390/insects11050323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 12/01/2022]
Abstract
The oriental fruit fly, Bactrocera dorsalis (Hendel), is one of the most devastating and highly invasive agricultural pests world-wide, resulting in severe economic loss. Thus, it is of great interest to understand the transcriptional changes that occur during the activation of its zygotic genome at the early stages of embryonic development, especially the expression of genes involved in sex determination and the cellularization processes. In this study, we applied Illumina sequencing to identify B. dorsalis sex determination genes and early zygotic genes by analyzing transcripts from three early embryonic stages at 0–1, 2–4, and 5–8 h post-oviposition, which include the initiation of sex determination and cellularization. These tests generated 13,489 unigenes with an average length of 2185 bp. In total, 1683, 3201 and 3134 unigenes had significant changes in expression levels at times after oviposition including at 2–4 h versus 0–1 h, 5–8 h versus 0–1 h, and 5–8 h versus 2–4 h, respectively. Clusters of gene orthology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations were performed throughout embryonic development to better understand the functions of differentially expressed unigenes. We observed that the RNA binding and spliceosome pathways were highly enriched and overrepresented during the early stage of embryogenesis. Additionally, transcripts for 21 sex-determination and three cellularization genes were identified, and expression pattern analysis revealed that the majority of these genes were highly expressed during embryogenesis. This study is the first assembly performed for B. dorsalis based on Illumina next-generation sequencing technology during embryogenesis. Our data should contribute significantly to the fundamental understanding of sex determination and early embryogenesis in tephritid fruit flies, and provide gene promoter and effector gene candidates for transgenic pest-management strategies for these economically important species.
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Affiliation(s)
- Wei Peng
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China
| | - Shuning Yu
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
| | - Alfred M. Handler
- USDA/ARS, Center for Medical, Agricultural and Veterinary Entomology, 1700 SW 23rd Drive, Gainesville, FL 32608, USA;
| | - Hongyu Zhang
- Key Laboratory of Horticultural Plant Biology (MOE), State Key Laboratory of Agricultural Microbiology, China-Australia Joint Research Centre for Horticultural and Urban Pests, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (W.P.); (S.Y.)
- Correspondence:
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26
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Ramat A, Garcia-Silva MR, Jahan C, Naït-Saïdi R, Dufourt J, Garret C, Chartier A, Cremaschi J, Patel V, Decourcelle M, Bastide A, Juge F, Simonelig M. The PIWI protein Aubergine recruits eIF3 to activate translation in the germ plasm. Cell Res 2020; 30:421-435. [PMID: 32132673 PMCID: PMC7196074 DOI: 10.1038/s41422-020-0294-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/11/2020] [Indexed: 12/13/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs) and PIWI proteins are essential in germ cells to repress transposons and regulate mRNAs. In Drosophila, piRNAs bound to the PIWI protein Aubergine (Aub) are transferred maternally to the embryo and regulate maternal mRNA stability through two opposite roles. They target mRNAs by incomplete base pairing, leading to their destabilization in the soma and stabilization in the germ plasm. Here, we report a function of Aub in translation. Aub is required for translational activation of nanos mRNA, a key determinant of the germ plasm. Aub physically interacts with the poly(A)-binding protein (PABP) and the translation initiation factor eIF3. Polysome gradient profiling reveals the role of Aub at the initiation step of translation. In the germ plasm, PABP and eIF3d assemble in foci that surround Aub-containing germ granules, and Aub acts with eIF3d to promote nanos translation. These results identify translational activation as a new mode of mRNA regulation by Aub, highlighting the versatility of PIWI proteins in mRNA regulation.
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Affiliation(s)
- Anne Ramat
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Maria-Rosa Garcia-Silva
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Camille Jahan
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Rima Naït-Saïdi
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Jérémy Dufourt
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Céline Garret
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Aymeric Chartier
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Julie Cremaschi
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Vipul Patel
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | | | | | - François Juge
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France
| | - Martine Simonelig
- mRNA Regulation and Development, Institute of Human Genetics, UMR9002 CNRS-Univ Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France.
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27
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The conserved regulatory basis of mRNA contributions to the early Drosophila embryo differs between the maternal and zygotic genomes. PLoS Genet 2020; 16:e1008645. [PMID: 32226006 PMCID: PMC7145188 DOI: 10.1371/journal.pgen.1008645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 04/09/2020] [Accepted: 02/03/2020] [Indexed: 02/06/2023] Open
Abstract
The gene products that drive early development are critical for setting up developmental trajectories in all animals. The earliest stages of development are fueled by maternally provided mRNAs until the zygote can take over transcription of its own genome. In early development, both maternally deposited and zygotically transcribed gene products have been well characterized in model systems. Previously, we demonstrated that across the genus Drosophila, maternal and zygotic mRNAs are largely conserved but also showed a surprising amount of change across species, with more differences evolving at the zygotic stage than the maternal stage. In this study, we use comparative methods to elucidate the regulatory mechanisms underlying maternal deposition and zygotic transcription across species. Through motif analysis, we discovered considerable conservation of regulatory mechanisms associated with maternal transcription, as compared to zygotic transcription. We also found that the regulatory mechanisms active in the maternal and zygotic genomes are quite different. For maternally deposited genes, we uncovered many signals that are consistent with transcriptional regulation at the level of chromatin state through factors enriched in the ovary, rather than precisely controlled gene-specific factors. For genes expressed only by the zygotic genome, we found evidence for previously identified regulators such as Zelda and GAGA-factor, with multiple analyses pointing toward gene-specific regulation. The observed mechanisms of regulation are consistent with what is known about regulation in these two genomes: during oogenesis, the maternal genome is optimized to quickly produce a large volume of transcripts to provide to the oocyte; after zygotic genome activation, mechanisms are employed to activate transcription of specific genes in a spatiotemporally precise manner. Thus the genetic architecture of the maternal and zygotic genomes, and the specific requirements for the transcripts present at each stage of embryogenesis, determine the regulatory mechanisms responsible for transcripts present at these stages.
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28
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Shin S, Hong JH, Na Y, Lee M, Qian WJ, Kim VN, Kim JS. Development of Multiplexed Immuno-N-Terminomics to Reveal the Landscape of Proteolytic Processing in Early Embryogenesis of Drosophila melanogaster. Anal Chem 2020; 92:4926-4934. [DOI: 10.1021/acs.analchem.9b05035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Sanghee Shin
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Ji Hye Hong
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Yongwoo Na
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Mihye Lee
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
| | - Wei-Jun Qian
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - V. Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
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29
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Sha QQ, Zhu YZ, Li S, Jiang Y, Chen L, Sun XH, Shen L, Ou XH, Fan HY. Characterization of zygotic genome activation-dependent maternal mRNA clearance in mouse. Nucleic Acids Res 2020; 48:879-894. [PMID: 31777931 PMCID: PMC6954448 DOI: 10.1093/nar/gkz1111] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 11/02/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022] Open
Abstract
An important event of the maternal-to-zygotic transition (MZT) in animal embryos is the elimination of a subset of the maternal transcripts that accumulated during oogenesis. In both invertebrates and vertebrates, a maternally encoded mRNA decay pathway (M-decay) acts before zygotic genome activation (ZGA) while a second pathway, which requires zygotic transcription, subsequently clears additional mRNAs (Z-decay). To date the mechanisms that activate the Z-decay pathway in mammalian early embryos have not been investigated. Here, we identify murine maternal transcripts that are degraded after ZGA and show that inhibition of de novo transcription stabilizes these mRNAs in mouse embryos. We show that YAP1-TEAD4 transcription factor-mediated transcription is essential for Z-decay in mouse embryos and that TEAD4-triggered zygotic expression of terminal uridylyltransferases TUT4 and TUT7 and mRNA 3'-oligouridylation direct Z-decay. Components of the M-decay pathway, including BTG4 and the CCR4-NOT deadenylase, continue to function in Z-decay but require reinforcement from the zygotic factors for timely removal of maternal mRNAs. A long 3'-UTR and active translation confer resistance of Z-decay transcripts to M-decay during oocyte meiotic maturation. The Z-decay pathway is required for mouse embryo development beyond the four-cell stage and contributes to the developmental competence of preimplantation embryos.
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Affiliation(s)
- Qian-Qian Sha
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China.,Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Ye-Zhang Zhu
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Sen Li
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Yu Jiang
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Lu Chen
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xiao-Hong Sun
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Li Shen
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xiang-Hong Ou
- Fertility Preservation Laboratory, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Heng-Yu Fan
- MOE Key Laboratory for Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China.,Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province; Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
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30
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Laver JD, Ly J, Winn JK, Karaiskakis A, Lin S, Nie K, Benic G, Jaberi-Lashkari N, Cao WX, Khademi A, Westwood JT, Sidhu SS, Morris Q, Angers S, Smibert CA, Lipshitz HD. The RNA-Binding Protein Rasputin/G3BP Enhances the Stability and Translation of Its Target mRNAs. Cell Rep 2020; 30:3353-3367.e7. [PMID: 32160542 DOI: 10.1016/j.celrep.2020.02.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 01/13/2020] [Accepted: 02/14/2020] [Indexed: 12/14/2022] Open
Abstract
G3BP RNA-binding proteins are important components of stress granules (SGs). Here, we analyze the role of the Drosophila G3BP Rasputin (RIN) in unstressed cells, where RIN is not SG associated. Immunoprecipitation followed by microarray analysis identifies over 550 mRNAs that copurify with RIN. The mRNAs found in SGs are long and translationally silent. In contrast, we find that RIN-bound mRNAs, which encode core components of the transcription, splicing, and translation machinery, are short, stable, and highly translated. We show that RIN is associated with polysomes and provide evidence for a direct role for RIN and its human homologs in stabilizing and upregulating the translation of their target mRNAs. We propose that when cells are stressed, the resulting incorporation of RIN/G3BPs into SGs sequesters them away from their short target mRNAs. This would downregulate the expression of these transcripts, even though they are not incorporated into stress granules.
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Affiliation(s)
- John D Laver
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Jimmy Ly
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Jamie K Winn
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Angelo Karaiskakis
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sichun Lin
- Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada
| | - Kun Nie
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Giulia Benic
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Nima Jaberi-Lashkari
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Alireza Khademi
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - J Timothy Westwood
- Department of Biology, University of Toronto, 3359 Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Sachdev S Sidhu
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | - Quaid Morris
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada; Vector Institute, 661 University Ave, Toronto, Ontario, Canada, M160 College Street, Toronto, ON M5G 1M1, Canada
| | - Stephane Angers
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
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Eichler CE, Hakes AC, Hull B, Gavis ER. Compartmentalized oskar degradation in the germ plasm safeguards germline development. eLife 2020; 9:49988. [PMID: 31909715 PMCID: PMC6986870 DOI: 10.7554/elife.49988] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 01/07/2020] [Indexed: 12/13/2022] Open
Abstract
Partitioning of mRNAs into ribonucleoprotein (RNP) granules supports diverse regulatory programs within the crowded cytoplasm. At least two types of RNP granules populate the germ plasm, a cytoplasmic domain at the posterior of the Drosophila oocyte and embryo. Germ granules deliver mRNAs required for germline development to pole cells, the germ cell progenitors. A second type of RNP granule, here named founder granules, contains oskar mRNA, which encodes the germ plasm organizer. Whereas oskar mRNA is essential for germ plasm assembly during oogenesis, we show that it is toxic to pole cells. Founder granules mediate compartmentalized degradation of oskar during embryogenesis to minimize its inheritance by pole cells. Degradation of oskar in founder granules is temporally and mechanistically distinct from degradation of oskar and other mRNAs during the maternal-to-zygotic transition. Our results show how compartmentalization in RNP granules differentially controls fates of mRNAs localized within the same cytoplasmic domain.
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Affiliation(s)
- Catherine E Eichler
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Anna C Hakes
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Brooke Hull
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University, Princeton, United States
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32
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3' UTRs Regulate Protein Functions by Providing a Nurturing Niche during Protein Synthesis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:95-104. [PMID: 31900325 DOI: 10.1101/sqb.2019.84.039206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Messenger RNAs (mRNAs) are the templates for protein synthesis as the coding region is translated into the amino acid sequence. mRNAs also contain 3' untranslated regions (3' UTRs) that harbor additional elements for the regulation of protein function. If the amino acid sequence of a protein is necessary and sufficient for its function, we call it 3' UTR-independent. In contrast, functions that are accomplished by protein complexes whose formation requires the presence of a specific 3' UTR are 3' UTR-dependent protein functions. We showed that 3' UTRs can regulate protein activity without affecting protein abundance, and alternative 3' UTRs can diversify protein functions. We currently think that the regulation of protein function by 3' UTRs is facilitated by the local environment at the site of protein synthesis, which we call the nurturing niche for nascent proteins. This niche is composed of the mRNA and the bound proteins that consist of RNA-binding proteins and recruited proteins. It enables the formation of specific protein complexes, as was shown for TIS granules, a recently discovered cytoplasmic membraneless organelle. This finding suggests that changing the niche for nascent proteins will alter protein activity and function, implying that cytoplasmic membraneless organelles can regulate protein function in a manner that is independent of protein abundance.
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33
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Narula A, Ellis J, Taliaferro JM, Rissland OS. Coding regions affect mRNA stability in human cells. RNA (NEW YORK, N.Y.) 2019; 25:1751-1764. [PMID: 31527111 PMCID: PMC6859850 DOI: 10.1261/rna.073239.119] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/09/2019] [Indexed: 05/05/2023]
Abstract
A new paradigm has emerged that coding regions can regulate mRNA stability in model organisms. Here, due to differences in cognate tRNA abundance, synonymous codons are translated at different speeds, and slow codons then stimulate mRNA decay. To ask if this phenomenon also occurs in humans, we isolated RNA stability effects due to coding regions using the human ORFeome collection. We find that many open reading frame (ORF) characteristics, such as length and secondary structure, fail to provide explanations for how coding regions alter mRNA stability, and, instead, that the ORF relies on translation to impact mRNA stability. Consistent with what has been seen in other organisms, codon use is related to the effects of ORFs on transcript stability. Importantly, we found instability-associated codons have longer A-site dwell times, suggesting for the first time in humans a connection between elongation speed and mRNA decay. Thus, we propose that codon usage alters decoding speeds and so affects human mRNA stability.
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Affiliation(s)
- Ashrut Narula
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James Ellis
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - J Matthew Taliaferro
- RNA Bioscience Initiative and Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Olivia S Rissland
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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34
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Chakravarty AK, Smejkal T, Itakura AK, Garcia DM, Jarosz DF. A Non-amyloid Prion Particle that Activates a Heritable Gene Expression Program. Mol Cell 2019; 77:251-265.e9. [PMID: 31757755 PMCID: PMC6980676 DOI: 10.1016/j.molcel.2019.10.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/29/2019] [Accepted: 10/17/2019] [Indexed: 11/16/2022]
Abstract
Spatiotemporal gene regulation is often driven by RNA-binding proteins that harbor long intrinsically disordered regions in addition to folded RNA-binding domains. We report that the disordered region of the evolutionarily ancient developmental regulator Vts1/Smaug drives self-assembly into gel-like condensates. These proteinaceous particles are not composed of amyloid, yet they are infectious, allowing them to act as a protein-based epigenetic element: a prion [SMAUG+]. In contrast to many amyloid prions, condensation of Vts1 enhances its function in mRNA decay, and its self-assembly properties are conserved over large evolutionary distances. Yeast cells harboring [SMAUG+] downregulate a coherent network of mRNAs and exhibit improved growth under nutrient limitation. Vts1 condensates formed from purified protein can transform naive cells to acquire [SMAUG+]. Our data establish that non-amyloid self-assembly of RNA-binding proteins can drive a form of epigenetics beyond the chromosome, instilling adaptive gene expression programs that are heritable over long biological timescales.
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Affiliation(s)
- Anupam K Chakravarty
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - Tina Smejkal
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - Alan K Itakura
- Department of Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - David M Garcia
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA
| | - Daniel F Jarosz
- Department of Chemical and Systems Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University, 269 Campus Drive, Stanford, CA 94305, USA.
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35
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Expression Analysis of mRNA Decay of Maternal Genes during Bombyx mori Maternal-to-Zygotic Transition. Int J Mol Sci 2019; 20:ijms20225651. [PMID: 31718114 PMCID: PMC6887711 DOI: 10.3390/ijms20225651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/06/2019] [Accepted: 11/06/2019] [Indexed: 11/24/2022] Open
Abstract
Maternal genes play an important role in the early embryonic development of the silkworm. Early embryonic development without new transcription depends on maternal components stored in the egg during oocyte maturation. The maternal-to-zygotic transition (MZT) is a tightly regulated process that includes maternal mRNAs elimination and zygotic transcription initiation. This process has been extensively studied within model species. Each model organism has a unique pattern of maternal transcriptional clearance classes in MZT. In this study, we identified 66 maternal genes through bioinformatics analysis and expression analysis in the eggs of silkworm virgin moths (Bombyx mori). All 66 maternal genes were expressed in vitellogenesis in day eight female pupae. During MZT, the degradation of maternal gene mRNAs could be divided into three clusters. We found that eight maternal genes of cluster 1 remained stable from 0 to 3.0 h, 17 maternal genes of cluster 2 were significantly decayed from 0.5 to 1.0 h and 41 maternal genes of cluster 3 were significantly decayed after 1.5 h. Therefore, the initial time-point of degradation of cluster 2 was earlier than that of cluster 3. The maternal gene mRNAs decay of clusters 2 and 3 is first initiated by maternal degradation activity. Our study expands upon the identification of silkworm maternal genes and provides a perspective for further research of the embryo development in Bombyx mori.
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36
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Abstract
Following fertilization, the two specified gametes must unite to create an entirely new organism. The genome is initially transcriptionally quiescent, allowing the zygote to be reprogrammed into a totipotent state. Gradually, the genome is activated through a process known as the maternal-to-zygotic transition, which enables zygotic gene products to replace the maternal supply that initiated development. This essential transition has been broadly characterized through decades of research in several model organisms. However, we still lack a full mechanistic understanding of how genome activation is executed and how this activation relates to the reprogramming of the zygotic chromatin architecture. Recent work highlights the central role of transcriptional activators and suggests that these factors may coordinate transcriptional activation with other developmental changes.
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37
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Warner MR, Qiu L, Holmes MJ, Mikheyev AS, Linksvayer TA. Convergent eusocial evolution is based on a shared reproductive groundplan plus lineage-specific plastic genes. Nat Commun 2019; 10:2651. [PMID: 31201311 PMCID: PMC6570765 DOI: 10.1038/s41467-019-10546-w] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/14/2019] [Indexed: 12/31/2022] Open
Abstract
Eusociality has convergently evolved multiple times, but the genomic basis of caste-based division of labor and degree to which independent origins of eusociality have utilized common genes remain largely unknown. Here we characterize caste-specific transcriptomic profiles across development and adult body segments from pharaoh ants (Monomorium pharaonis) and honey bees (Apis mellifera), representing two independent origins of eusociality. We identify a substantial shared core of genes upregulated in the abdomens of queen ants and honey bees that also tends to be upregulated in mated female flies, suggesting that these genes are part of a conserved insect reproductive groundplan. Outside of this shared groundplan, few genes are differentially expressed in common. Instead, the majority of the thousands of caste-associated genes are plastically expressed, rapidly evolving, and relatively evolutionarily young. These results emphasize that the recruitment of both highly conserved and lineage-specific genes underlie the convergent evolution of novel traits such as eusociality. Eusocial caste systems have evolved independently multiple times. Here, Warner et al. investigate the amount of shared vs. lineage-specific genes involved in the evolution of caste in pharaoh ants and honey bees by comparing transcriptomes across tissues, developmental stages, and castes.
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Affiliation(s)
| | - Lijun Qiu
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Michael J Holmes
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan.,School of Life and Environmental Science, University of Sydney, Sydney, 2006, Australia
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan.,Research School of Biology, Australian National University, Canberra, 0200, Australia
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38
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Vastenhouw NL, Cao WX, Lipshitz HD. The maternal-to-zygotic transition revisited. Development 2019; 146:146/11/dev161471. [PMID: 31189646 DOI: 10.1242/dev.161471] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The development of animal embryos is initially directed by maternal gene products. Then, during the maternal-to-zygotic transition (MZT), developmental control is handed to the zygotic genome. Extensive research in both vertebrate and invertebrate model organisms has revealed that the MZT can be subdivided into two phases, during which very different modes of gene regulation are implemented: initially, regulation is exclusively post-transcriptional and post-translational, following which gradual activation of the zygotic genome leads to predominance of transcriptional regulation. These changes in the gene expression program of embryos are precisely controlled and highly interconnected. Here, we review current understanding of the mechanisms that underlie handover of developmental control during the MZT.
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Affiliation(s)
- Nadine L Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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39
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Teixeira FK, Lehmann R. Translational Control during Developmental Transitions. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032987. [PMID: 30082467 DOI: 10.1101/cshperspect.a032987] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The many steps of gene expression, from the transcription of a gene to the production of its protein product, are well understood. Yet, transcriptional regulation has been the focal point for the study of gene expression during development. However, quantitative studies reveal that messenger RNA (mRNA) levels are not necessarily good predictors of the respective proteins' levels in a cell. This discrepancy is, at least in part, the result of developmentally regulated, translational mechanisms that control the spatiotemporal regulation of gene expression. In this review, we focus on translational regulatory mechanisms mediating global transitions in gene expression: the shift from the maternal to the embryonic developmental program in the early embryo and the switch from the self-renewal of stem cells to differentiation in the adult.
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Affiliation(s)
| | - Ruth Lehmann
- Howard Hughes Medical Institute (HHMI) and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, New York 10016
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40
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Hanyu-Nakamura K, Matsuda K, Cohen SM, Nakamura A. Pgc suppresses the zygotically acting RNA decay pathway to protect germ plasm RNAs in the Drosophila embryo. Development 2019; 146:dev.167056. [PMID: 30890569 DOI: 10.1242/dev.167056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 03/11/2019] [Indexed: 11/20/2022]
Abstract
Specification of germ cells is pivotal to ensure continuation of animal species. In many animal embryos, germ cell specification depends on maternally supplied determinants in the germ plasm. Drosophila polar granule component (pgc) mRNA is a component of the germ plasm. pgc encodes a small protein that is transiently expressed in newly formed pole cells, the germline progenitors, where it globally represses mRNA transcription. pgc is also required for pole cell survival, but the mechanism linking transcriptional repression to pole cell survival remains elusive. We report that pole cells lacking pgc show premature loss of germ plasm mRNAs, including the germ cell survival factor nanos, and undergo apoptosis. We found that pgc- pole cells misexpress multiple miRNA genes. Reduction of miRNA pathway activity in pgc- embryos partially suppressed germ plasm mRNA degradation and pole cell death, suggesting that Pgc represses zygotic miRNA transcription in pole cells to protect germ plasm mRNAs. Interestingly, germ plasm mRNAs are protected from miRNA-mediated degradation in vertebrates, albeit by a different mechanism. Thus, independently evolved mechanisms are used to silence miRNAs during germ cell specification.
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Affiliation(s)
- Kazuko Hanyu-Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Kazuki Matsuda
- Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Stephen M Cohen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N Copenhagen, Denmark
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan .,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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41
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Comparative transcriptome analysis explores maternal to zygotic transition during Eriocheir sinensis early embryogenesis. Gene 2019; 685:12-20. [PMID: 30321661 DOI: 10.1016/j.gene.2018.10.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 09/27/2018] [Accepted: 10/11/2018] [Indexed: 11/21/2022]
Abstract
The maternal genome directs almost all aspects of early animal development. As development proceeds, the elimination of maternal gene products and zygotic genome activation (ZGA) occur during the maternal to zygotic transition (MZT). To study the molecular mechanisms regulating this developmental event in Eriocheir sinensis, RNA-Seq technology was applied to generate comprehensive information on transcriptome dynamics during early embryonic stages. In total, 32,088 annotated unigenes were obtained from the transcriptomes of fertilized eggs and embryos at the cleavage (2-4 cell) and blastula stage. A total of 566 maternal genes and 1165 zygotic genes were isolated, among which 103 and 266 genes were predicted conserved maternal transcripts (COMATs) and conserved zygotic transcripts (COZYTs), respectively. The COMATs performed housekeeping gene functions and may be essential for initiating early embryogenesis of the Bilateria. Furthermore, 87, 76 and 117 differentially expressed genes associated with the MZT, morphogenesis and immunity were identified when compared the three transcriptomic datasets. We also unmask that the MZT takes place around the cleavage stage, when the genes involved in the clearance of maternal gene products and the ZGA were significantly up-regulated. Taken together, these datasets provide a valuable resource for understanding the mechanisms of early developmental events in E. sinensis, and facilitate further studies on molecular mechanisms of asynchronous development in crabs.
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42
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Chang H, Yeo J, Kim JG, Kim H, Lim J, Lee M, Kim HH, Ohk J, Jeon HY, Lee H, Jung H, Kim KW, Kim VN. Terminal Uridylyltransferases Execute Programmed Clearance of Maternal Transcriptome in Vertebrate Embryos. Mol Cell 2019; 70:72-82.e7. [PMID: 29625039 DOI: 10.1016/j.molcel.2018.03.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/07/2018] [Accepted: 03/01/2018] [Indexed: 12/26/2022]
Abstract
During the maternal-to-zygotic transition (MZT), maternal RNAs are actively degraded and replaced by newly synthesized zygotic transcripts in a highly coordinated manner. However, it remains largely unknown how maternal mRNA decay is triggered in early vertebrate embryos. Here, through genome-wide profiling of RNA abundance and 3' modification, we show that uridylation is induced at the onset of maternal mRNA clearance. The temporal control of uridylation is conserved in vertebrates. When the homologs of terminal uridylyltransferases TUT4 and TUT7 (TUT4/7) are depleted in zebrafish and Xenopus, maternal mRNA clearance is significantly delayed, leading to developmental defects during gastrulation. Short-tailed mRNAs are selectively uridylated by TUT4/7, with the highly uridylated transcripts degraded faster during the MZT than those with unmodified poly(A) tails. Our study demonstrates that uridylation plays a crucial role in timely mRNA degradation, thereby allowing the progression of early development.
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Affiliation(s)
- Hyeshik Chang
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
| | - Jinah Yeo
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
| | - Jeong-Gyun Kim
- Department of Molecular Medicine and Biopharmaceutical Science, Seoul National University, Seoul 08826, Korea
| | - Hyunjoon Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
| | - Jaechul Lim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Mihye Lee
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea
| | - Hyun Ho Kim
- Department of Molecular Medicine and Biopharmaceutical Science, Seoul National University, Seoul 08826, Korea
| | - Jiyeon Ohk
- Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hee-Yeon Jeon
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Hyunsook Lee
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Hosung Jung
- Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Kyu-Won Kim
- Department of Molecular Medicine and Biopharmaceutical Science, Seoul National University, Seoul 08826, Korea
| | - V Narry Kim
- Center for RNA Research, Institute for Basic Science, Seoul 08826, Korea; School of Biological Sciences, Seoul National University, Seoul 08826, Korea.
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43
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Kami D, Kitani T, Nakamura A, Wakui N, Mizutani R, Ohue M, Kametani F, Akimitsu N, Gojo S. The DEAD-box RNA-binding protein DDX6 regulates parental RNA decay for cellular reprogramming to pluripotency. PLoS One 2018; 13:e0203708. [PMID: 30273347 PMCID: PMC6166933 DOI: 10.1371/journal.pone.0203708] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/24/2018] [Indexed: 12/30/2022] Open
Abstract
Cellular transitions and differentiation processes require mRNAs supporting the new phenotype but also the clearance of existing mRNAs for the parental phenotype. Cellular reprogramming from fibroblasts to induced pluripotent stem cells (iPSCs) occurs at the early stage of mesenchymal epithelial transition (MET) and involves drastic morphological changes. We examined the molecular mechanism for MET, focusing on RNA metabolism. DDX6, an RNA helicase, was indispensable for iPSC formation, in addition to RO60 and RNY1, a non-coding RNA, which form complexes involved in intracellular nucleotide sensing. RO60/RNY1/DDX6 complexes formed prior to processing body formation, which is central to RNA metabolism. The abrogation of DDX6 expression inhibited iPSC generation, which was mediated by RNA decay targeting parental mRNAs supporting mesenchymal phenotypes, along with microRNAs, such as miR-302b-3p. These results show that parental mRNA clearance is a prerequisite for cellular reprogramming and that DDX6 plays a central role in this process.
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Affiliation(s)
- Daisuke Kami
- Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomoya Kitani
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Akihiro Nakamura
- Department of Pediatric Cardiology and Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Naoki Wakui
- Department of Computer Science, School of Computing, Tokyo Institute of Technology, Tokyo, Japan
| | - Rena Mizutani
- Radioisotope Center, The University of Tokyo, Tokyo, Japan
| | - Masahito Ohue
- Department of Computer Science, School of Computing, Tokyo Institute of Technology, Tokyo, Japan
| | - Fuyuki Kametani
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | | | - Satoshi Gojo
- Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- * E-mail:
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44
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Ylla G, Piulachs MD, Belles X. Comparative Transcriptomics in Two Extreme Neopterans Reveals General Trends in the Evolution of Modern Insects. iScience 2018; 4:164-179. [PMID: 30240738 PMCID: PMC6147021 DOI: 10.1016/j.isci.2018.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/13/2018] [Accepted: 05/23/2018] [Indexed: 01/08/2023] Open
Abstract
The success of neopteran insects, with 1 million species described, is associated with developmental innovations such as holometaboly and the evolution from short to long germband embryogenesis. To unveil the mechanisms underlining these innovations, we compared gene expression during the ontogeny of two extreme neopterans, the cockroach Blattella germanica (polyneopteran, hemimetabolan, and short germband species) and the fly Drosophila melanogaster (endopterygote, holometabolan, and long germband species). Results revealed that genes associated with metamorphosis are predominantly expressed in late nymphal stages in B. germanica and in the early-mid embryo in D. melanogaster. In B. germanica the maternal to zygotic transition (MZT) concentrates early in embryogenesis, when juvenile hormone factors are significantly expressed. In D. melanogaster, the MZT extends throughout embryogenesis, during which time juvenile hormone factors appear to be unimportant. These differences possibly reflect broad trends in the evolution of development within neopterans, related to the germband type and the metamorphosis mode. Transcriptomes of cockroaches and flies show key differences along development Cockroaches and flies express metamorphosis factors with distinct timings in ontogeny Cockroaches methylate DNA in early embryogenesis, whereas flies do not MZT is limited to the early embryo in cockroaches, but it extends until hatching in flies
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Affiliation(s)
- Guillem Ylla
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain
| | - Maria-Dolors Piulachs
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain
| | - Xavier Belles
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Passeig Marítim 37, 08003 Barcelona, Spain.
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Treen N, Heist T, Wang W, Levine M. Depletion of Maternal Cyclin B3 Contributes to Zygotic Genome Activation in the Ciona Embryo. Curr Biol 2018; 28:1150-1156.e4. [PMID: 29576477 PMCID: PMC5996753 DOI: 10.1016/j.cub.2018.02.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/18/2017] [Accepted: 02/16/2018] [Indexed: 10/17/2022]
Abstract
Most animal embryos display a delay in the activation of zygotic transcription during early embryogenesis [1]. This process is thought to help coordinate rapid increases in cell number during early development [2]. The timing of zygotic genome activation (ZGA) during the maternal-to-zygotic transition (MZT) remains uncertain despite extensive efforts. We explore ZGA in the simple protovertebrate, Ciona intestinalis. Single-cell RNA sequencing (RNA-seq) assays identified Cyclin B3 (Ccnb3) as a putative mediator of ZGA. Maternal Ccnb3 transcripts rapidly diminish in abundance during the onset of zygotic transcription at the 8-cell and 16-cell stages. Disruption of Ccnb3 activity results in precocious activation of zygotic transcription, while overexpression abolishes normal activation. These observations suggest that the depletion of maternal Cyclin B3 products is a critical component of the MZT and ZGA. We discuss evidence that this mechanism might play a conserved role in the MZT of other metazoans, including mice and humans.
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Affiliation(s)
- Nicholas Treen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
| | - Tyler Heist
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Wei Wang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Michael Levine
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Lefebvre FA, Lécuyer É. Flying the RNA Nest: Drosophila Reveals Novel Insights into the Transcriptome Dynamics of Early Development. J Dev Biol 2018; 6:jdb6010005. [PMID: 29615554 PMCID: PMC5875563 DOI: 10.3390/jdb6010005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/01/2018] [Accepted: 03/05/2018] [Indexed: 01/02/2023] Open
Abstract
Early development is punctuated by a series of pervasive and fast paced transitions. These events reshape a differentiated oocyte into a totipotent embryo and allow it to gradually mount a genetic program of its own, thereby framing a new organism. Specifically, developmental transitions that ensure the maternal to embryonic control of developmental events entail a deep remodeling of transcriptional and transcriptomic landscapes. Drosophila provides an elegant and genetically tractable system to investigate these conserved changes at a dazzling developmental pace. Here, we review recent studies applying emerging technologies such as ribosome profiling, in situ Hi-C chromatin probing and live embryo RNA imaging to investigate the transcriptional dynamics at play during Drosophila embryogenesis. In light of this new literature, we revisit the main models of zygotic genome activation (ZGA). We also review the contributions played by zygotic transcription in shaping embryogenesis and explore emerging concepts of processes such as transcriptional bursting and transcriptional memory.
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Affiliation(s)
- Fabio Alexis Lefebvre
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada.
- Département de Biochimie, Université de Montréal, Montréal, QC H3T 1J4, Canada.
| | - Éric Lécuyer
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, QC H2W 1R7, Canada.
- Département de Biochimie, Université de Montréal, Montréal, QC H3T 1J4, Canada.
- Division of Experimental Medicine, McGill University, Montréal, QC H3A 0G4, Canada.
- IRCM, RNA Biology Laboratory, 110 Avenue des Pins, Ouest, Montréal, QC H2W 1R7, Canada.
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Abstract
The activation of the zygotic genome and onset of transcription in blastula embryos is linked to changes in cell behavior and remodeling of the cell cycle and constitutes a transition from exclusive maternal to zygotic control of development. This step in development is referred to as mid-blastula transition and has served as a paradigm for the link between developmental program and cell behavior and morphology. Here, we discuss the mechanism and functional relationships between the zygotic genome activation and cell cycle control during mid-blastula transition with a focus on Drosophila embryos.
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Affiliation(s)
- Boyang Liu
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig-Weg11, Göttingen 37077, Germany
| | - Jörg Grosshans
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig-Weg11, Göttingen 37077, Germany.
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Xie Y, Blankenship JT. Differentially-dimensioned furrow formation by zygotic gene expression and the MBT. PLoS Genet 2018; 14:e1007174. [PMID: 29337989 PMCID: PMC5786337 DOI: 10.1371/journal.pgen.1007174] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 01/26/2018] [Accepted: 12/29/2017] [Indexed: 12/17/2022] Open
Abstract
Despite extensive work on the mechanisms that generate plasma membrane furrows, understanding how cells are able to dynamically regulate furrow dimensions is an unresolved question. Here, we present an in-depth characterization of furrow behaviors and their regulation in vivo during early Drosophila morphogenesis. We show that the deepening in furrow dimensions with successive nuclear cycles is largely due to the introduction of a new, rapid ingression phase (Ingression II). Blocking the midblastula transition (MBT) by suppressing zygotic transcription through pharmacological or genetic means causes the absence of Ingression II, and consequently reduces furrow dimensions. The analysis of compound chromosomes that produce chromosomal aneuploidies suggests that multiple loci on the X, II, and III chromosomes contribute to the production of differentially-dimensioned furrows, and we track the X-chromosomal contribution to furrow lengthening to the nullo gene product. We further show that checkpoint proteins are required for furrow lengthening; however, mitotic phases of the cell cycle are not strictly deterministic for furrow dimensions, as a decoupling of mitotic phases with periods of active ingression occurs as syncytial furrow cycles progress. Finally, we examined the turnover of maternal gene products and find that this is a minor contributor to the developmental regulation of furrow morphologies. Our results suggest that cellularization dynamics during cycle 14 are a continuation of dynamics established during the syncytial cycles and provide a more nuanced view of developmental- and MBT-driven morphogenesis. One of the primary events that must occur repeatedly throughout a complex animal’s lifetime is the ingression of a plasma membrane furrow. Furrow formation and ingression are requisite elements of cell division, and drive the physical separation of one cell into two cells. However, the mechanisms that permit an embryo to change the length and size of a furrow are unclear. Here, we show that a combination of higher ingression rates and longer duration phases drive changes in furrow dimensions through the introduction of a new ingression phase. These changes are driven by the embryo’s own genome, and suggest that zygotic transcription controls organismal form at an earlier time point than previously appreciated. Additionally, the failure to properly lengthen furrows as development proceeds causes defects in chromosome segregation during cell division and results in massive genomic instability. Our data demonstrate the importance of the dynamic regulation of furrow dimensions to organismal form and viability.
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Affiliation(s)
- Yi Xie
- Department of Biological Sciences, University of Denver, Denver, CO, United States of America
| | - J. Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO, United States of America
- * E-mail:
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Despic V, Neugebauer KM. RNA tales – how embryos read and discard messages from mom. J Cell Sci 2018; 131:jcs.201996. [DOI: 10.1242/jcs.201996] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Following fertilization, embryos develop for a substantial amount of time with a transcriptionally silent genome. Thus, early development is maternally programmed, as it solely relies on RNAs and proteins that are provided by the female gamete. However, these maternal instructions are not sufficient to support later steps of embryogenesis and are therefore gradually replaced by novel products synthesized from the zygotic genome. This switch in the origin of molecular players that drive early development is known as the maternal-to-zygotic transition (MZT). MZT is a universal phenomenon among all metazoans and comprises two interconnected processes: maternal mRNA degradation and the transcriptional awakening of the zygotic genome. The recent adaptation of high-throughput methods for use in embryos has deepened our knowledge of the molecular principles underlying MZT. These mechanisms comprise conserved strategies for RNA regulation that operate in many well-studied cellular contexts but that have adapted differently to early development. In this Review, we will discuss advances in our understanding of post-transcriptional regulatory pathways that drive maternal mRNA clearance during MZT, with an emphasis on recent data in zebrafish embryos on codon-mediated mRNA decay, the contributions of microRNAs (miRNAs) and RNA-binding proteins to this process, and the roles of RNA modifications in the stability control of maternal mRNAs.
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Affiliation(s)
- Vladimir Despic
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY 10065, USA
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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Davidson PL, Koch BJ, Schnitzler CE, Henry JQ, Martindale MQ, Baxevanis AD, Browne WE. The maternal-zygotic transition and zygotic activation of the Mnemiopsis leidyi genome occurs within the first three cleavage cycles. Mol Reprod Dev 2017; 84:1218-1229. [PMID: 29068507 DOI: 10.1002/mrd.22926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/03/2017] [Indexed: 12/20/2022]
Abstract
The maternal-zygotic transition (MZT) describes the developmental reprogramming of gene expression marked by the degradation of maternally supplied gene products and activation of the zygotic genome. While the timing and duration of the MZT vary among taxa, little is known about early-stage transcriptional dynamics in the non-bilaterian phylum Ctenophora. We sought to better understand the extent of maternal mRNA loading and subsequent differential transcript abundance during the earliest stages of development by performing comprehensive RNA-sequencing-based analyses of mRNA abundance in single- and eight-cell stage embryos in the lobate ctenophore Mnemiopsis leidyi. We found 1,908 contigs with significant differential abundance between single- and eight-cell stages, of which 1,208 contigs were more abundant at the single-cell stage and 700 contigs were more abundant at the eight-cell stage. Of the differentially abundant contigs, 267 were exclusively present in the eight-cell samples, providing strong evidence that both the MZT and zygotic genome activation (ZGA) have commenced by the eight-cell stage. Many highly abundant transcripts encode genes involved in molecular mechanisms critical to the MZT, such as maternal transcript degradation, serine/threonine kinase activity, and chromatin remodeling. Our results suggest that chromosomal restructuring, which is critical to ZGA and the initiation of transcriptional regulation necessary for normal development, begins by the third cleavage within 1.5 hr post-fertilization in M. leidyi.
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Affiliation(s)
| | - Bernard J Koch
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Christine E Schnitzler
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.,Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, Florida.,Department of Biology, University of Florida, Gainesville, Florida
| | - Jonathan Q Henry
- Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois
| | - Mark Q Martindale
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, Florida.,Department of Biology, University of Florida, Gainesville, Florida
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - William E Browne
- Department of Biology, University of Miami, Coral Gables, Florida
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