1
|
Hawkins LM, Wang C, Chaput D, Batra M, Marsilia C, Awshah D, Suvorova ES. The Crk4-Cyc4 complex regulates G 2/M transition in Toxoplasma gondii. EMBO J 2024; 43:2094-2126. [PMID: 38600241 PMCID: PMC11148040 DOI: 10.1038/s44318-024-00095-4] [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: 01/10/2024] [Revised: 03/12/2024] [Accepted: 03/26/2024] [Indexed: 04/12/2024] Open
Abstract
A versatile division of apicomplexan parasites and a dearth of conserved regulators have hindered the progress of apicomplexan cell cycle studies. While most apicomplexans divide in a multinuclear fashion, Toxoplasma gondii tachyzoites divide in the traditional binary mode. We previously identified five Toxoplasma CDK-related kinases (Crk). Here, we investigated TgCrk4 and its cyclin partner TgCyc4. We demonstrated that TgCrk4 regulates conventional G2 phase processes, such as repression of chromosome rereplication and centrosome reduplication, and acts upstream of the spindle assembly checkpoint. The spatial TgCyc4 dynamics supported the TgCrk4-TgCyc4 complex role in the coordination of chromosome and centrosome cycles. We also identified a dominant TgCrk4-TgCyc4 complex interactor, TgiRD1 protein, related to DNA replication licensing factor CDT1 but played no role in licensing DNA replication in the G1 phase. Our results showed that TgiRD1 also plays a role in controlling chromosome and centrosome reduplication. Global phosphoproteome analyses identified TgCrk4 substrates, including TgORC4, TgCdc20, TgGCP2, and TgPP2ACA. Importantly, the phylogenetic and structural studies suggest the Crk4-Cyc4 complex is limited to a minor group of the binary dividing apicomplexans.
Collapse
Affiliation(s)
- Lauren M Hawkins
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Chengqi Wang
- College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Dale Chaput
- Proteomics Core, College of Arts and Sciences, University of South Florida, Tampa, FL, 33612, USA
| | - Mrinalini Batra
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Clem Marsilia
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Danya Awshah
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Elena S Suvorova
- Division of Infectious Diseases, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA.
| |
Collapse
|
2
|
Graham EL, Fernandez J, Gandhi S, Choudhry I, Kellam N, LaRocque JR. The impact of developmental stage, tissue type, and sex on DNA double-strand break repair in Drosophila melanogaster. PLoS Genet 2024; 20:e1011250. [PMID: 38683763 PMCID: PMC11057719 DOI: 10.1371/journal.pgen.1011250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/04/2024] [Indexed: 05/02/2024] Open
Abstract
Accurate repair of DNA double-strand breaks (DSBs) is essential for the maintenance of genome integrity, as failure to repair DSBs can result in cell death. The cell has evolved two main mechanisms for DSB repair: non-homologous end-joining (NHEJ) and homology-directed repair (HDR), which includes single-strand annealing (SSA) and homologous recombination (HR). While certain factors like age and state of the chromatin are known to influence DSB repair pathway choice, the roles of developmental stage, tissue type, and sex have yet to be elucidated in multicellular organisms. To examine the influence of these factors, DSB repair in various embryonic developmental stages, larva, and adult tissues in Drosophila melanogaster was analyzed through molecular analysis of the DR-white assay using Tracking across Indels by DEcomposition (TIDE). The proportion of HR repair was highest in tissues that maintain the canonical (G1/S/G2/M) cell cycle and suppressed in both terminally differentiated and polyploid tissues. To determine the impact of sex on repair pathway choice, repair in different tissues in both males and females was analyzed. When molecularly examining tissues containing mostly somatic cells, males and females demonstrated similar proportions of HR and NHEJ. However, when DSB repair was analyzed in male and female premeiotic germline cells utilizing phenotypic analysis of the DR-white assay, there was a significant decrease in HR in females compared to males. This study describes the impact of development, tissue-specific cycling profile, and, in some cases, sex on DSB repair outcomes, underscoring the complexity of repair in multicellular organisms.
Collapse
Affiliation(s)
- Elizabeth L. Graham
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Joel Fernandez
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Shagun Gandhi
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Iqra Choudhry
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Natalia Kellam
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| | - Jeannine R. LaRocque
- Department of Human Science, School of Health, Georgetown University Medical Center, Washington, District of Columbia, United States of America
| |
Collapse
|
3
|
Sotomayor-Lugo F, Iglesias-Barrameda N, Castillo-Aleman YM, Casado-Hernandez I, Villegas-Valverde CA, Bencomo-Hernandez AA, Ventura-Carmenate Y, Rivero-Jimenez RA. The Dynamics of Histone Modifications during Mammalian Zygotic Genome Activation. Int J Mol Sci 2024; 25:1459. [PMID: 38338738 PMCID: PMC10855761 DOI: 10.3390/ijms25031459] [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: 12/29/2023] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Mammalian fertilization initiates the reprogramming of oocytes and sperm, forming a totipotent zygote. During this intricate process, the zygotic genome undergoes a maternal-to-zygotic transition (MZT) and subsequent zygotic genome activation (ZGA), marking the initiation of transcriptional control and gene expression post-fertilization. Histone modifications are pivotal in shaping cellular identity and gene expression in many mammals. Recent advances in chromatin analysis have enabled detailed explorations of histone modifications during ZGA. This review delves into conserved and unique regulatory strategies, providing essential insights into the dynamic changes in histone modifications and their variants during ZGA in mammals. The objective is to explore recent advancements in leading mechanisms related to histone modifications governing this embryonic development phase in depth. These considerations will be useful for informing future therapeutic approaches that target epigenetic regulation in diverse biological contexts. It will also contribute to the extensive areas of evolutionary and developmental biology and possibly lay the foundation for future research and discussion on this seminal topic.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Rene Antonio Rivero-Jimenez
- Abu Dhabi Stem Cells Center, Abu Dhabi P.O. Box 4600, United Arab Emirates; (F.S.-L.); (N.I.-B.); (Y.M.C.-A.); (I.C.-H.); (C.A.V.-V.); (A.A.B.-H.); (Y.V.-C.)
| |
Collapse
|
4
|
Zhang Y, Yu H, Wang D, Lei X, Meng Y, Zhang N, Chen F, Lv L, Pan Q, Qin H, Zhang Z, van Aalten DMF, Yuan K. Protein O-GlcNAcylation homeostasis regulates facultative heterochromatin to fine-tune sog-Dpp signaling during Drosophila early embryogenesis. J Genet Genomics 2023; 50:948-959. [PMID: 37286164 DOI: 10.1016/j.jgg.2023.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 04/30/2023] [Accepted: 05/18/2023] [Indexed: 06/09/2023]
Abstract
Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly shortgastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.
Collapse
Affiliation(s)
- Yaowen Zhang
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Haibin Yu
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Dandan Wang
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Xiaoyun Lei
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yang Meng
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Na Zhang
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Fang Chen
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Lu Lv
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Qian Pan
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Hongtao Qin
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan University, Changsha, Hunan 410082, China
| | - Zhuohua Zhang
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Daan M F van Aalten
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK; Department of Molecular Biology and Genetics, University of Aarhus, Aarhus 8000, Denmark.
| | - Kai Yuan
- Center for Medical Genetics, School of Life Sciences & Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; The Biobank of Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
| |
Collapse
|
5
|
Ostberg H, Boehm Vock L, Bloch-Qazi MC. Advanced maternal age has negative multigenerational impacts during Drosophila melanogaster embryogenesis. CURRENT RESEARCH IN INSECT SCIENCE 2023; 4:100068. [PMID: 38161993 PMCID: PMC10757284 DOI: 10.1016/j.cris.2023.100068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 01/03/2024]
Abstract
Increasing maternal age is commonly accompanied by decreased fitness in offspring. In Drosophila melanogaster, maternal senescence negatively affects multiple facets of offspring phenotype and fitness. These maternal effects are particularly large on embryonic viability. Identifying which embryonic stages are disrupted can indicate mechanisms of maternal effect senescence. Some maternal effects can also carry-over to subsequent generations. We examined potential multi- and transgenerational effects maternal senescence on embryonic development in two laboratory strains of D. melanogaster. We categorized the developmental stages of embryos from every combination of old and young mother, grandmother and great grandmother. We then modelled embryonic survival across the stages and compared these models among the multigenerational maternal age groups in order to identify which developmental processes were most sensitive to the effects of maternal effect senescence. Maternal effect senescence has negative multigenerational effects on multiple embryonic stages, indicating that maternal provisioning and, possibly epigenetics, but not mutation accumulation, contribute to decreased offspring survival. This study shows the large, early and multi-faceted nature of maternal effects senescence in an insect population.
Collapse
Affiliation(s)
- Halie Ostberg
- Department of Biology, Gustavus Adolphus College, 800 West College Avenue, Saint Peter, MN 56082, USA
| | - Laura Boehm Vock
- Department of Mathematics and Computer Science, Gustavus Adolphus College, 800 West College Avenue, Saint Peter, MN 56082, USA
- Department of Mathematics, Statistics, and Computer Science, Saint Olaf College, 1520 St. Olaf Avenue, Northfield, MN 55057, USA
| | - Margaret C. Bloch-Qazi
- Department of Biology, Gustavus Adolphus College, 800 West College Avenue, Saint Peter, MN 56082, USA
| |
Collapse
|
6
|
Colgren J, Burkhardt P. Evolution: Was the nuclear-to-cytoplasmic ratio a key factor in the origin of animal multicellularity? Curr Biol 2023; 33:R298-R300. [PMID: 37098330 DOI: 10.1016/j.cub.2023.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The ichthyosporean Sphaeroforma arctica, a protist closely related to animals, displays coenocytic development followed by cellularization and cell release. A new study reveals that the nuclear-to-cytoplasmic ratio drives cellularization in these fascinating organisms.
Collapse
Affiliation(s)
- Jeffrey Colgren
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway.
| | - Pawel Burkhardt
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway.
| |
Collapse
|
7
|
Örkenby L, Skog S, Ekman H, Gozzo A, Kugelberg U, Ramesh R, Magadi S, Zambanini G, Nordin A, Cantú C, Nätt D, Öst A. Stress-sensitive dynamics of miRNAs and Elba1 in Drosophila embryogenesis. Mol Syst Biol 2023; 19:e11148. [PMID: 36938679 PMCID: PMC10167479 DOI: 10.15252/msb.202211148] [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: 05/29/2022] [Revised: 02/15/2023] [Accepted: 02/23/2023] [Indexed: 03/21/2023] Open
Abstract
Early-life stress can result in life-long effects that impact adult health and disease risk, but little is known about how such programming is established and maintained. Here, we show that such epigenetic memories can be initiated in the Drosophila embryo before the major wave of zygotic transcription, and higher-order chromatin structures are established. An early short heat shock results in elevated levels of maternal miRNA and reduced levels of a subgroup of zygotic genes in stage 5 embryos. Using a Dicer-1 mutant, we show that the stress-induced decrease in one of these genes, the insulator-binding factor Elba1, is dependent on functional miRNA biogenesis. Reduction in Elba1 correlates with the upregulation of early developmental genes and promotes a sustained weakening of heterochromatin in the adult fly as indicated by an increased expression of the PEV wm4h reporter. We propose that maternal miRNAs, retained in response to an early embryonic heat shock, shape the subsequent de novo heterochromatin establishment that occurs during early development via direct or indirect regulation of some of the earliest expressed genes, including Elba1.
Collapse
Affiliation(s)
- Lovisa Örkenby
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Signe Skog
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Helen Ekman
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Alessandro Gozzo
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Unn Kugelberg
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Rashmi Ramesh
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Srivathsa Magadi
- Division of Neurobiology (NEURO), Linköping University, Linköping, Sweden
| | - Gianluca Zambanini
- Division of Molecular Medicine and Virology (MMV), Linköping University, Linköping, Sweden
| | - Anna Nordin
- Division of Molecular Medicine and Virology (MMV), Linköping University, Linköping, Sweden
| | - Claudio Cantú
- Division of Molecular Medicine and Virology (MMV), Linköping University, Linköping, Sweden
| | - Daniel Nätt
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Anita Öst
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| |
Collapse
|
8
|
Hirai K, Inoue YH, Matsuda M. Mitotic progression and dual spindle formation caused by spindle association of de novo-formed microtubule-organizing centers in parthenogenetic embryos of Drosophila ananassae. Genetics 2022; 223:6896485. [PMID: 36516293 PMCID: PMC9910410 DOI: 10.1093/genetics/iyac178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 09/17/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
Facultative parthenogenesis occurs in many animal species that typically undergo sexual reproduction. In Drosophila, such development from unfertilized eggs involves diploidization after completion of meiosis, but the exact mechanism remains unclear. Here we used a laboratory stock of Drosophila ananassae that has been maintained parthenogenetically to cytologically examine the initial events of parthenogenesis. Specifically, we determined whether the requirements for centrosomes and diploidization that are essential for developmental success can be overcome. As a primal deviation from sexually reproducing (i.e. sexual) strains of the same species, free asters emerged from the de novo formation of centrosome-like structures in the cytosol of unfertilized eggs. Those microtubule-organizing centers had distinct roles in the earliest cycles of parthenogenetic embryos with respect to mitotic progression and arrangement of mitotic spindles. In the first cycle, an anastral bipolar spindle self-assembled around a haploid set of replicated chromosomes. Participation of at least one microtubule-organizing center in the spindle was necessary for mitotic progression into anaphase. In particular, the first mitosis involving a monastral bipolar spindle resulted in haploid daughter nuclei, one of which was associated with a microtubule-organizing center whereas the other was not. Remarkably, in the following cycle, biastral and anastral bipolar spindles formed that were frequently arranged in tandem by sharing an aster with bidirectional connections at their central poles. We propose that, for diploidization of haploid nuclei, unfertilized parthenogenetic embryos utilize dual spindles during the second mitosis, as occurs for the first mitosis in normal fertilized eggs.
Collapse
Affiliation(s)
| | - Yoshihiro H Inoue
- Biomedical Research Center, Kyoto Institute of Technology, Kyoto, Kyoto 606-8585, Japan
| | - Muneo Matsuda
- Department of Biology, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan
| |
Collapse
|
9
|
Balachandra S, Sarkar S, Amodeo AA. The Nuclear-to-Cytoplasmic Ratio: Coupling DNA Content to Cell Size, Cell Cycle, and Biosynthetic Capacity. Annu Rev Genet 2022; 56:165-185. [PMID: 35977407 PMCID: PMC10165727 DOI: 10.1146/annurev-genet-080320-030537] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Though cell size varies between different cells and across species, the nuclear-to-cytoplasmic (N/C) ratio is largely maintained across species and within cell types. A cell maintains a relatively constant N/C ratio by coupling DNA content, nuclear size, and cell size. We explore how cells couple cell division and growth to DNA content. In some cases, cells use DNA as a molecular yardstick to control the availability of cell cycle regulators. In other cases, DNA sets a limit for biosynthetic capacity. Developmentally programmed variations in the N/C ratio for a given cell type suggest that a specific N/C ratio is required to respond to given physiological demands. Recent observations connecting decreased N/C ratios with cellular senescence indicate that maintaining the proper N/C ratio is essential for proper cellular functioning. Together, these findings suggest a causative, not simply correlative, role for the N/C ratio in regulating cell growth and cell cycle progression.
Collapse
Affiliation(s)
- Shruthi Balachandra
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA; ,
| | - Sharanya Sarkar
- Department of Microbiology and Immunology, Dartmouth College, Hanover, New Hampshire, USA;
| | - Amanda A Amodeo
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA; ,
| |
Collapse
|
10
|
Warecki B, Titen SWA, Alam MS, Vega G, Lemseffer N, Hug K, Minden JS, Sullivan W. Wolbachia action in the sperm produces developmentally deferred chromosome segregation defects during the Drosophila mid-blastula transition. eLife 2022; 11:81292. [PMID: 36149408 PMCID: PMC9507124 DOI: 10.7554/elife.81292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/09/2022] [Indexed: 11/29/2022] Open
Abstract
Wolbachia, a vertically transmitted endosymbiont infecting many insects, spreads rapidly through uninfected populations by a mechanism known as cytoplasmic incompatibility (CI). In CI, a paternally delivered modification of the sperm leads to chromatin defects and lethality during and after the first mitosis of embryonic development in multiple species. However, whether CI-induced defects in later stage embryos are a consequence of the first division errors or caused by independent defects remains unresolved. To address this question, we focused on ~1/3 of embryos from CI crosses in Drosophila simulans that develop apparently normally through the first and subsequent pre-blastoderm divisions before exhibiting mitotic errors during the mid-blastula transition and gastrulation. We performed single embryo PCR and whole genome sequencing to find a large percentage of these developed CI-derived embryos bypass the first division defect. Using fluorescence in situ hybridization, we find increased chromosome segregation errors in gastrulating CI-derived embryos that had avoided the first division defect. Thus, Wolbachia action in the sperm induces developmentally deferred defects that are not a consequence of the first division errors. Like the immediate defect, the delayed defect is rescued through crosses to infected females. These studies inform current models on the molecular and cellular basis of CI.
Collapse
Affiliation(s)
- Brandt Warecki
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Simon William Abraham Titen
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States.,Department of Biology and Chemistry, California State University Monterey Bay, Seaside, United States
| | - Mohammad Shahriyar Alam
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Giovanni Vega
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Nassim Lemseffer
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Karen Hug
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| | - Jonathan S Minden
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, United States
| | - William Sullivan
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States
| |
Collapse
|
11
|
Diegmiller R, Nunley H, Shvartsman SY, Imran Alsous J. Quantitative models for building and growing fated small cell networks. Interface Focus 2022; 12:20210082. [PMID: 35865502 PMCID: PMC9184967 DOI: 10.1098/rsfs.2021.0082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/31/2022] [Indexed: 02/07/2023] Open
Abstract
Small cell clusters exhibit numerous phenomena typically associated with complex systems, such as division of labour and programmed cell death. A conserved class of such clusters occurs during oogenesis in the form of germline cysts that give rise to oocytes. Germline cysts form through cell divisions with incomplete cytokinesis, leaving cells intimately connected through intercellular bridges that facilitate cyst generation, cell fate determination and collective growth dynamics. Using the well-characterized Drosophila melanogaster female germline cyst as a foundation, we present mathematical models rooted in the dynamics of cell cycle proteins and their interactions to explain the generation of germline cell lineage trees (CLTs) and highlight the diversity of observed CLT sizes and topologies across species. We analyse competing models of symmetry breaking in CLTs to rationalize the observed dynamics and robustness of oocyte fate specification, and highlight remaining gaps in knowledge. We also explore how CLT topology affects cell cycle dynamics and synchronization and highlight mechanisms of intercellular coupling that underlie the observed collective growth patterns during oogenesis. Throughout, we point to similarities across organisms that warrant further investigation and comment on the extent to which experimental and theoretical findings made in model systems extend to other species.
Collapse
Affiliation(s)
- Rocky Diegmiller
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Hayden Nunley
- Flatiron Institute, Simons Foundation, New York, NY, USA
| | - Stanislav Y. Shvartsman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA,Department of Molecular Biology, Princeton University, Princeton, NJ, USA,Flatiron Institute, Simons Foundation, New York, NY, USA
| | | |
Collapse
|
12
|
Restriction of subapical proteins during cellularization depends on the onset of zygotic transcription and the formin Dia. Dev Biol 2022; 487:110-121. [PMID: 35525304 DOI: 10.1016/j.ydbio.2022.04.012] [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: 11/18/2021] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 11/21/2022]
Abstract
Cortical domains are characterized by spatially restricted polarity proteins. The pattern of cortical domains is dynamic and changes during cell differentiation and development. Although there is a good understanding for how the cortical pattern is maintained, e. g. by mutual antagonism, less is known about how the initial pattern is established, and its dynamics coordinated with developmental progression. Here we investigate the initial restriction of subapical marker proteins during the syncytial-cellular transition in Drosophila embryos. The subapical markers Canoe/Afadin, the complex ELMO-Sponge, Baz and Arm become initially restricted between apical and lateral domains during cellularization. We define the role of zygotic genome activation as a timer for subapical domain formation. Subapical markers remained widely spread in embryos treated with α-amanitin and became precociously restricted in mutant embryos with premature zygotic transcription. In contrast, remodeling of the nuclear division cycle without cytokinesis to a full cell cycle is not a prerequisite for subapical domain formation, since we observed timely subapical restriction in embryos undergoing an extra nuclear cycle. We provide evidence that earliest subapical markers ELMO-Sponge and Canoe are required for subapical accumulation of Baz. Supporting an important role of cortical F-actin in subapical restriction, we found that the formin Dia was required for Baz restriction, and its distribution depended on the onset of zygotic gene expression. In summary, we define zygotic transcription as a timer, to which subapical markers respond in a dia-dependent mechanism.
Collapse
|
13
|
Identification of replication fork-associated proteins in Drosophila embryos and cultured cells using iPOND coupled to quantitative mass spectrometry. Sci Rep 2022; 12:6903. [PMID: 35484306 PMCID: PMC9050644 DOI: 10.1038/s41598-022-10821-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Replication of the eukaryotic genome requires the formation of thousands of replication forks that must work in concert to accurately replicate the genetic and epigenetic information. Defining replication fork-associated proteins is a key step in understanding how genomes are replicated and repaired in the context of chromatin to maintain genome stability. To identify replication fork-associated proteins, we performed iPOND (Isolation of Proteins on Nascent DNA) coupled to quantitative mass spectrometry in Drosophila embryos and cultured cells. We identified 76 and 278 fork-associated proteins in post-MZT embryos and Drosophila cultured S2 cells, respectively. By performing a targeted screen of a subset of these proteins, we demonstrate that BRWD3, a targeting specificity factor for the DDB1/Cul4 ubiquitin ligase complex (CRL4), functions at or in close proximity to replication forks to promote fork progression and maintain genome stability. Altogether, our work provides a valuable resource for those interested in DNA replication, repair and chromatin assembly during development.
Collapse
|
14
|
Shindo Y, Brown MG, Amodeo AA. Versatile roles for histones in early development. Curr Opin Cell Biol 2022; 75:102069. [PMID: 35279563 PMCID: PMC9064922 DOI: 10.1016/j.ceb.2022.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/30/2022] [Accepted: 02/04/2022] [Indexed: 11/28/2022]
Abstract
The nuclear environment changes dramatically over the course of early development. Histones are core chromatin components that play critical roles in regulating gene expression and nuclear architecture. Additionally, the embryos of many species, including Drosophila, Zebrafish, and Xenopus use the availability of maternally deposited histones to time critical early embryonic events including cell cycle slowing and zygotic genome activation. Here, we review recent insights into how histones control early development. We first discuss the regulation of chromatin functions through interaction of histones and transcription factors, incorporation of variant histones, and histone post-translational modifications. We also highlight emerging roles for histones as developmental regulators independent of chromatin association.
Collapse
Affiliation(s)
- Yuki Shindo
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA.
| | - Madeleine G Brown
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Amanda A Amodeo
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA.
| |
Collapse
|
15
|
Prudêncio P, Savisaar R, Rebelo K, Martinho RG, Carmo-Fonseca M. Transcription and splicing dynamics during early Drosophila development. RNA (NEW YORK, N.Y.) 2022; 28:139-161. [PMID: 34667107 PMCID: PMC8906543 DOI: 10.1261/rna.078933.121] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/23/2021] [Indexed: 05/03/2023]
Abstract
Widespread cotranscriptional splicing has been demonstrated from yeast to human. However, most studies to date addressing the kinetics of splicing relative to transcription used either Saccharomyces cerevisiae or metazoan cultured cell lines. Here, we adapted native elongating transcript sequencing technology (NET-seq) to measure cotranscriptional splicing dynamics during the early developmental stages of Drosophila melanogaster embryos. Our results reveal the position of RNA polymerase II (Pol II) when both canonical and recursive splicing occur. We found heterogeneity in splicing dynamics, with some RNAs spliced immediately after intron transcription, whereas for other transcripts no splicing was observed over the first 100 nt of the downstream exon. Introns that show splicing completion before Pol II has reached the end of the downstream exon are necessarily intron-defined. We studied the splicing dynamics of both nascent pre-mRNAs transcribed in the early embryo, which have few and short introns, as well as pre-mRNAs transcribed later in embryonic development, which contain multiple long introns. As expected, we found a relationship between the proportion of spliced reads and intron size. However, intron definition was observed at all intron sizes. We further observed that genes transcribed in the early embryo tend to be isolated in the genome whereas genes transcribed later are often overlapped by a neighboring convergent gene. In isolated genes, transcription termination occurred soon after the polyadenylation site, while in overlapped genes, Pol II persisted associated with the DNA template after cleavage and polyadenylation of the nascent transcript. Taken together, our data unravel novel dynamic features of Pol II transcription and splicing in the developing Drosophila embryo.
Collapse
Affiliation(s)
- Pedro Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
- Algarve Biomedical Center Research Institute (ABC-RI), Universidade do Algarve, 8005-139 Faro, Portugal
| | - Rosina Savisaar
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Kenny Rebelo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Rui Gonçalo Martinho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
- Algarve Biomedical Center Research Institute (ABC-RI), Universidade do Algarve, 8005-139 Faro, Portugal
- Department of Medical Sciences and Institute for Biomedicine (iBiMED), Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| |
Collapse
|
16
|
Ma X, Øvrebø JI, Thompson EM. Evolution of CDK1 Paralog Specializations in a Lineage With Fast Developing Planktonic Embryos. Front Cell Dev Biol 2022; 9:770939. [PMID: 35155443 PMCID: PMC8832800 DOI: 10.3389/fcell.2021.770939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 12/27/2021] [Indexed: 12/03/2022] Open
Abstract
The active site of the essential CDK1 kinase is generated by core structural elements, among which the PSTAIRE motif in the critical αC-helix, is universally conserved in the single CDK1 ortholog of all metazoans. We report serial CDK1 duplications in the chordate, Oikopleura. Paralog diversifications in the PSTAIRE, activation loop substrate binding platform, ATP entrance site, hinge region, and main Cyclin binding interface, have undergone positive selection to subdivide ancestral CDK1 functions along the S-M phase cell cycle axis. Apparent coevolution of an exclusive CDK1d:Cyclin Ba/b pairing is required for oogenic meiosis and early embryogenesis, a period during which, unusually, CDK1d, rather than Cyclin Ba/b levels, oscillate, to drive very rapid cell cycles. Strikingly, the modified PSTAIRE of odCDK1d shows convergence over great evolutionary distance with plant CDKB, and in both cases, these variants exhibit increased specialization to M-phase.
Collapse
Affiliation(s)
- Xiaofei Ma
- College of Life Sciences, Northwest Normal University, Lanzhou, China
- Sars International Centre, University of Bergen, Bergen, Norway
- *Correspondence: Xiaofei Ma, , ; Eric M. Thompson,
| | - Jan Inge Øvrebø
- Sars International Centre, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Eric M. Thompson
- Sars International Centre, University of Bergen, Bergen, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- *Correspondence: Xiaofei Ma, , ; Eric M. Thompson,
| |
Collapse
|
17
|
Mofatteh M, Echegaray-Iturra F, Alamban A, Dalla Ricca F, Bakshi A, Aydogan MG. Autonomous clocks that regulate organelle biogenesis, cytoskeletal organization, and intracellular dynamics. eLife 2021; 10:e72104. [PMID: 34586070 PMCID: PMC8480978 DOI: 10.7554/elife.72104] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/14/2021] [Indexed: 12/27/2022] Open
Abstract
How do cells perceive time? Do cells use temporal information to regulate the production/degradation of their enzymes, membranes, and organelles? Does controlling biological time influence cytoskeletal organization and cellular architecture in ways that confer evolutionary and physiological advantages? Potential answers to these fundamental questions of cell biology have historically revolved around the discussion of 'master' temporal programs, such as the principal cyclin-dependent kinase/cyclin cell division oscillator and the circadian clock. In this review, we provide an overview of the recent evidence supporting an emerging concept of 'autonomous clocks,' which under normal conditions can be entrained by the cell cycle and/or the circadian clock to run at their pace, but can also run independently to serve their functions if/when these major temporal programs are halted/abrupted. We begin the discussion by introducing recent developments in the study of such clocks and their roles at different scales and complexities. We then use current advances to elucidate the logic and molecular architecture of temporal networks that comprise autonomous clocks, providing important clues as to how these clocks may have evolved to run independently and, sometimes at the cost of redundancy, have strongly coupled to run under the full command of the cell cycle and/or the circadian clock. Next, we review a list of important recent findings that have shed new light onto potential hallmarks of autonomous clocks, suggestive of prospective theoretical and experimental approaches to further accelerate their discovery. Finally, we discuss their roles in health and disease, as well as possible therapeutic opportunities that targeting the autonomous clocks may offer.
Collapse
Affiliation(s)
- Mohammad Mofatteh
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Fabio Echegaray-Iturra
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Andrew Alamban
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Francesco Dalla Ricca
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Anand Bakshi
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Mustafa G Aydogan
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| |
Collapse
|
18
|
Abou Chakra M, Isserlin R, Tran TN, Bader GD. Control of tissue development and cell diversity by cell cycle-dependent transcriptional filtering. eLife 2021; 10:64951. [PMID: 34212855 PMCID: PMC8279763 DOI: 10.7554/elife.64951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 07/01/2021] [Indexed: 12/12/2022] Open
Abstract
Cell cycle duration changes dramatically during development, starting out fast to generate cells quickly and slowing down over time as the organism matures. The cell cycle can also act as a transcriptional filter to control the expression of long gene transcripts, which are partially transcribed in short cycles. Using mathematical simulations of cell proliferation, we identify an emergent property that this filter can act as a tuning knob to control gene transcript expression, cell diversity, and the number and proportion of different cell types in a tissue. Our predictions are supported by comparison to single-cell RNA-seq data captured over embryonic development. Additionally, evolutionary genome analysis shows that fast-developing organisms have a narrow genomic distribution of gene lengths while slower developers have an expanded number of long genes. Our results support the idea that cell cycle dynamics may be important across multicellular animals for controlling gene transcript expression and cell fate.
Collapse
Affiliation(s)
| | - Ruth Isserlin
- The Donnelly Centre, University of Toronto, Toronto, Canada
| | - Thinh N Tran
- The Donnelly Centre, University of Toronto, Toronto, Canada
| | - Gary D Bader
- The Donnelly Centre, University of Toronto, Toronto, Canada
| |
Collapse
|
19
|
Abstract
Understanding the mechanisms of embryonic cell cycles is a central goal of developmental biology, as the regulation of the cell cycle must be closely coordinated with other events during early embryogenesis. Quantitative imaging approaches have recently begun to reveal how the cell cycle oscillator is controlled in space and time, and how it is integrated with mechanical signals to drive morphogenesis. Here, we discuss how the Drosophila embryo has served as an excellent model for addressing the molecular and physical mechanisms of embryonic cell cycles, with comparisons to other model systems to highlight conserved and species-specific mechanisms. We describe how the rapid cleavage divisions characteristic of most metazoan embryos require chemical waves and cytoplasmic flows to coordinate morphogenesis across the large expanse of the embryo. We also outline how, in the late cleavage divisions, the cell cycle is inter-regulated with the activation of gene expression to ensure a reliable maternal-to-zygotic transition. Finally, we discuss how precise transcriptional regulation of the timing of mitosis ensures that tissue morphogenesis and cell proliferation are tightly controlled during gastrulation.
Collapse
Affiliation(s)
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27705, USA
| |
Collapse
|
20
|
Liu B, Zhao H, Wu K, Großhans J. Temporal Gradients Controlling Embryonic Cell Cycle. BIOLOGY 2021; 10:biology10060513. [PMID: 34207742 PMCID: PMC8228447 DOI: 10.3390/biology10060513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022]
Abstract
Simple Summary Embryonic cells sense temporal gradients of regulatory signals to determine whether and when to proceed or remodel the cell cycle. Such a control mechanism is allowed to accurately link the cell cycle with the developmental program, including cell differentiation, morphogenesis, and gene expression. The mid-blastula transition has been a paradigm for timing in early embryogenesis in frog, fish, and fly, among others. It has been argued for decades now if the events associated with the mid-blastula transition, i.e., the onset of zygotic gene expression, remodeling of the cell cycle, and morphological changes, are determined by a control mechanism or by absolute time. Recent studies indicate that multiple independent signals and mechanisms contribute to the timing of these different processes. Here, we focus on the mechanisms for cell cycle remodeling, specifically in Drosophila, which relies on gradual changes of the signal over time. We discuss pathways for checkpoint activation, decay of Cdc25 protein levels, as well as depletion of deoxyribonucleotide metabolites and histone proteins. The gradual changes of these signals are linked to Cdk1 activity by readout mechanisms involving thresholds. Abstract Cell proliferation in early embryos by rapid cell cycles and its abrupt pause after a stereotypic number of divisions present an attractive system to study the timing mechanism in general and its coordination with developmental progression. In animals with large eggs, such as Xenopus, zebrafish, or Drosophila, 11–13 very fast and synchronous cycles are followed by a pause or slowdown of the cell cycle. The stage when the cell cycle is remodeled falls together with changes in cell behavior and activation of the zygotic genome and is often referred to as mid-blastula transition. The number of fast embryonic cell cycles represents a clear and binary readout of timing. Several factors controlling the cell cycle undergo dynamics and gradual changes in activity or concentration and thus may serve as temporal gradients. Recent studies have revealed that the gradual loss of Cdc25 protein, gradual depletion of free deoxyribonucleotide metabolites, or gradual depletion of free histone proteins impinge on Cdk1 activity in a threshold-like manner. In this review, we will highlight with a focus on Drosophila studies our current understanding and recent findings on the generation and readout of these temporal gradients, as well as their position within the regulatory network of the embryonic cell cycle.
Collapse
Affiliation(s)
- Boyang Liu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (B.L.); (H.Z.); (K.W.)
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan 250012, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan 250012, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan 250012, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan 250012, China
| | - Han Zhao
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (B.L.); (H.Z.); (K.W.)
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan 250012, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan 250012, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan 250012, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan 250012, China
| | - Keliang Wu
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (B.L.); (H.Z.); (K.W.)
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan 250012, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan 250012, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan 250012, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan 250012, China
| | - Jörg Großhans
- Department of Biology, Philipps University, 35043 Marburg, Germany
- Correspondence:
| |
Collapse
|
21
|
Modeling the role for nuclear import dynamics in the early embryonic cell cycle. Biophys J 2021; 120:4277-4286. [PMID: 34022240 DOI: 10.1016/j.bpj.2021.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/22/2021] [Accepted: 05/06/2021] [Indexed: 11/21/2022] Open
Abstract
Nuclear composition determines nuclear function. The early embryos of many species begin life with large pools of maternally provided components that become rapidly imported into an increasing number of nuclei as the cells undergo repeated cleavage divisions. Because early cell cycles are too fast for nuclei to achieve steady-state nucleocytoplasmic partitioning, the composition of cleavage stage nuclei is likely dominated by nuclear import. The end of the rapid cleavage stage and onset of major zygotic transcription, known as the mid-blastula transition (MBT), is controlled by the ratio of nuclei/cytoplasm, indicating that changes in nuclear composition likely mediate MBT timing. Here, we explore how different nuclear import regimes can affect protein accumulation in the nucleus in the early Drosophila embryo. We find that nuclear import differs dramatically for a general nuclear cargo (NLS (nuclear localization signal)-mRFP) and a proposed MBT regulator (histone H3). We show that nuclear import rates of NLS-mRFP in a given nucleus remain relatively unchanged throughout the cleavage cycles, whereas those of H3 halve with each cycle. We model these two distinct modes of nuclear import as "nucleus-limited" and "import-limited" and examine how the two different modes can contribute to different protein accumulation dynamics. Finally, we incorporate these distinct modes of nuclear import into a model for cell-cycle regulation at the MBT and find that the import-limited H3 dynamics contribute to increased robustness and allow for stepwise cell-cycle slowing at the MBT.
Collapse
|
22
|
Li M, Zhao Q, Belloli R, Duffy CR, Cai HN. Insulator foci distance correlates with cellular and nuclear morphology in early Drosophila embryos. Dev Biol 2021; 476:189-199. [PMID: 33844976 DOI: 10.1016/j.ydbio.2021.03.022] [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: 09/23/2020] [Revised: 02/16/2021] [Accepted: 03/26/2021] [Indexed: 11/25/2022]
Abstract
The three-dimensional (3D) organization of the genome is highly dynamic, changing during development and varying across different tissues and cell types. Recent studies indicate that these changes alter regulatory interactions, leading to changes in gene expression. Despite its importance, the mechanisms that influence genomic organization remain poorly understood. We have previously identified a network of chromatin boundary elements, or insulators, in the Drosophila Antennapedia homeotic complex (ANT-C). These genomic elements interact with one another to tether chromatin loops that could block or promote enhancer-promoter interactions. To understand the function of these insulators, we assessed their interactions by measuring their 3D nuclear distance in developing animal tissues. Our data suggest that the ANT-C Hox complex might be in a folded or looped configuration rather than in a random or extended form. The architecture of the ANT-C complex, as read out by the pair-wise distance between insulators, undergoes a strong compression during late embryogenesis, coinciding with the reduction of cell and nuclear diameters due to continued cell divisions in post-cleavage cells. Our results suggest that genomic architecture and gene regulation may be influenced by cellular morphology and movement during development.
Collapse
Affiliation(s)
- Mo Li
- Department of Cellular Biology, University of Georgia, Athens GA, 30602, USA
| | - Qing Zhao
- Department of Cellular Biology, University of Georgia, Athens GA, 30602, USA
| | - Ryan Belloli
- Department of Cellular Biology, University of Georgia, Athens GA, 30602, USA
| | - Carly R Duffy
- Department of Cellular Biology, University of Georgia, Athens GA, 30602, USA
| | - Haini N Cai
- Department of Cellular Biology, University of Georgia, Athens GA, 30602, USA.
| |
Collapse
|
23
|
The nuclear to cytoplasmic ratio directly regulates zygotic transcription in Drosophila through multiple modalities. Proc Natl Acad Sci U S A 2021; 118:2010210118. [PMID: 33790005 DOI: 10.1073/pnas.2010210118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Early embryos must rapidly generate large numbers of cells to form an organism. Many species accomplish this through a series of rapid, reductive, and transcriptionally silent cleavage divisions. Previous work has demonstrated that the number of divisions before both cell cycle elongation and zygotic genome activation (ZGA) is regulated by the ratio of nuclear content to cytoplasm (N/C). To understand how the N/C ratio affects the timing of ZGA, we directly assayed the behavior of several previously identified N/C ratio-dependent genes using the MS2-MCP reporter system in living Drosophila embryos with altered ploidy and cell cycle durations. For every gene that we examined, we found that nascent RNA output per cycle is delayed in haploid embryos. Moreover, we found that the N/C ratio influences transcription through three overlapping modes of action. For some genes (knirps, fushi tarazu, and snail), the effect of ploidy can be primarily attributed to changes in cell cycle duration. However, additional N/C ratio-mediated mechanisms contribute significantly to transcription delays for other genes. For giant and bottleneck, the kinetics of transcription activation are significantly disrupted in haploids, while for frühstart and Krüppel, the N/C ratio controls the probability of transcription initiation. Our data demonstrate that the regulatory elements of N/C ratio-dependent genes respond directly to the N/C ratio through multiple modes of regulation.
Collapse
|
24
|
Shi Q, Meng Z, Tian XX, Wang YF, Wang WH. Identification and validation of a hub gene prognostic index for hepatocellular carcinoma. Future Oncol 2021; 17:2193-2208. [PMID: 33620260 DOI: 10.2217/fon-2020-1112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aims: We aim to provide new insights into the mechanisms of hepatocellular carcinoma (HCC) and identify key genes as biomarkers for the prognosis of HCC. Materials & methods: Differentially expressed genes between HCC tissues and normal tissues were identified via the Gene Expression Omnibus tool. The top ten hub genes screened by the degree of the protein nodes in the protein-protein interaction network also showed significant associations with overall survival in HCC patients. Results: A prognostic model containing a five-gene signature was constructed to predict the prognosis of HCC via multivariate Cox regression analysis. Conclusion: This study identified a novel five-gene signature (CDK1, CCNB1, CCNB2, BUB1 and KIF11) as a significant independent prognostic factor.
Collapse
Affiliation(s)
- Q Shi
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Z Meng
- The People's Hospital of Henan Province, Zhengzhou, Henan, 450003, China
| | - X X Tian
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Y F Wang
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - W H Wang
- The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| |
Collapse
|
25
|
Yu H, Li Y, Li L, Huang J, Wang X, Tang R, Jiang Z, Lv L, Chen F, Yu C, Yuan K. Functional reciprocity of proteins involved in mitosis and endocytosis. FEBS J 2020; 288:5850-5866. [PMID: 33300206 DOI: 10.1111/febs.15664] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/29/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022]
Abstract
Mitosis and endocytosis are two fundamental cellular processes essential for maintaining a eukaryotic life. Mitosis partitions duplicated chromatin enveloped in the nuclear membrane into two new cells, whereas endocytosis takes in extracellular substances through membrane invagination. These two processes are spatiotemporally separated and seemingly unrelated. However, recent studies have uncovered that endocytic proteins have moonlighting functions in mitosis, and mitotic complexes manifest additional roles in endocytosis. In this review, we summarize important proteins or protein complexes that participate in both processes, compare their mechanism of action, and discuss the rationale behind this multifunctionality. We also speculate on the possible origin of the functional reciprocity from an evolutionary perspective.
Collapse
Affiliation(s)
- Haibin Yu
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Yinshuang Li
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Li Li
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | | | - Xujuan Wang
- The High School Attached to Hunan Normal University, Changsha, China
| | - Ruijun Tang
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zhenghui Jiang
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lu Lv
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Fang Chen
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Chunhong Yu
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Kai Yuan
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,The Biobank of Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
26
|
Strong IJT, Lei X, Chen F, Yuan K, O’Farrell PH. Interphase-arrested Drosophila embryos activate zygotic gene expression and initiate mid-blastula transition events at a low nuclear-cytoplasmic ratio. PLoS Biol 2020; 18:e3000891. [PMID: 33090988 PMCID: PMC7608951 DOI: 10.1371/journal.pbio.3000891] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/03/2020] [Accepted: 09/14/2020] [Indexed: 11/18/2022] Open
Abstract
Externally deposited eggs begin development with an immense cytoplasm and a single overwhelmed nucleus. Rapid mitotic cycles restore normality as the ratio of nuclei to cytoplasm (N/C) increases. A threshold N/C has been widely proposed to activate zygotic genome transcription and onset of morphogenesis at the mid-blastula transition (MBT). To test whether a threshold N/C is required for these events, we blocked N/C increase by down-regulating cyclin/Cdk1 to arrest early cell cycles in Drosophila. Embryos that were arrested two cell cycles prior to the normal MBT activated widespread transcription of the zygotic genome including genes previously described as N/C dependent. Zygotic transcription of these genes largely retained features of their regulation in space and time. Furthermore, zygotically regulated post-MBT events such as cellularization and gastrulation movements occurred in these cell cycle-arrested embryos. These results are not compatible with models suggesting that these MBT events are directly coupled to N/C. Cyclin/Cdk1 activity normally declines in tight association with increasing N/C and is regulated by N/C. By experimentally promoting the decrease in cyclin/Cdk1, we uncoupled MBT from N/C increase, arguing that N/C-guided down-regulation of cyclin/Cdk1 is sufficient for genome activation and MBT.
Collapse
Affiliation(s)
- Isaac J. T. Strong
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Xiaoyun Lei
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Fang Chen
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Kai Yuan
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Patrick H. O’Farrell
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| |
Collapse
|
27
|
Koromila T, Gao F, Iwasaki Y, He P, Pachter L, Gergen JP, Stathopoulos A. Odd-paired is a pioneer-like factor that coordinates with Zelda to control gene expression in embryos. eLife 2020; 9:e59610. [PMID: 32701060 PMCID: PMC7417190 DOI: 10.7554/elife.59610] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 07/22/2020] [Indexed: 01/29/2023] Open
Abstract
Pioneer factors such as Zelda (Zld) help initiate zygotic transcription in Drosophila early embryos, but whether other factors support this dynamic process is unclear. Odd-paired (Opa), a zinc-finger transcription factor expressed at cellularization, controls the transition of genes from pair-rule to segmental patterns along the anterior-posterior axis. Finding that Opa also regulates expression through enhancer sog_Distal along the dorso-ventral axis, we hypothesized Opa's role is more general. Chromatin-immunoprecipitation (ChIP-seq) confirmed its in vivo binding to sog_Distal but also identified widespread binding throughout the genome, comparable to Zld. Furthermore, chromatin assays (ATAC-seq) demonstrate that Opa, like Zld, influences chromatin accessibility genome-wide at cellularization, suggesting both are pioneer factors with common as well as distinct targets. Lastly, embryos lacking opa exhibit widespread, late patterning defects spanning both axes. Collectively, these data suggest Opa is a general timing factor and likely late-acting pioneer factor that drives a secondary wave of zygotic gene expression.
Collapse
Affiliation(s)
- Theodora Koromila
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Fan Gao
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Yasuno Iwasaki
- Stony Brook University, Department of Biochemistry and Cell Biology and Center for Developmental GeneticsStony BrookUnited States
| | - Peng He
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - Lior Pachter
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| | - J Peter Gergen
- Stony Brook University, Department of Biochemistry and Cell Biology and Center for Developmental GeneticsStony BrookUnited States
| | - Angelike Stathopoulos
- California Institute of Technology, Division of Biology and Biological EngineeringPasadenaUnited States
| |
Collapse
|
28
|
Samata M, Alexiadis A, Richard G, Georgiev P, Nuebler J, Kulkarni T, Renschler G, Basilicata MF, Zenk FL, Shvedunova M, Semplicio G, Mirny L, Iovino N, Akhtar A. Intergenerationally Maintained Histone H4 Lysine 16 Acetylation Is Instructive for Future Gene Activation. Cell 2020; 182:127-144.e23. [DOI: 10.1016/j.cell.2020.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 02/22/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
|
29
|
Tang R, Jiang Z, Chen F, Yu W, Fan K, Tan J, Zhang Z, Liu X, Li P, Yuan K. The Kinase Activity of Drosophila BubR1 Is Required for Insulin Signaling-Dependent Stem Cell Maintenance. Cell Rep 2020; 31:107794. [PMID: 32579921 DOI: 10.1016/j.celrep.2020.107794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/29/2020] [Accepted: 05/31/2020] [Indexed: 02/06/2023] Open
Abstract
As a core component of the mitotic checkpoint complex, BubR1 has a modular organization of molecular functions, with KEN box and other motifs at the N terminus inhibiting the anaphase-promoting complex/cyclosome, and a kinase domain at the C terminus, whose function remains unsettled, especially at organismal levels. We generate knock-in BubR1 mutations in the Drosophila genome to separately disrupt the KEN box and the kinase domain. All of the mutants are homozygously viable and fertile and show no defects in mitotic progression. The mutants without kinase activity have an increased lifespan and phenotypic changes associated with attenuated insulin signaling, including reduced InR on the cell membrane, weakened PI3K and AKT activity, and elevated expression of dFoxO targets. The BubR1 kinase-dead mutants have a reduced cap cell number in female germaria, which can be rescued by expressing a constitutively active InR. We conclude that one major physiological role of BubR1 kinase in Drosophila is to modulate insulin signaling.
Collapse
Affiliation(s)
- Ruijun Tang
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Zhenghui Jiang
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Fang Chen
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Weiyu Yu
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Kaijing Fan
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Jieqiong Tan
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Zhuohua Zhang
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.
| | - Pishun Li
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Kai Yuan
- Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurosurgery, Xiangya Hospital, and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China; Center for Clinical Biorepositories and Biospecimens, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
| |
Collapse
|
30
|
Cattenoz PB, Sakr R, Pavlidaki A, Delaporte C, Riba A, Molina N, Hariharan N, Mukherjee T, Giangrande A. Temporal specificity and heterogeneity of Drosophila immune cells. EMBO J 2020; 39:e104486. [PMID: 32162708 PMCID: PMC7298292 DOI: 10.15252/embj.2020104486] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/18/2020] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
Immune cells provide defense against non-self and have recently been shown to also play key roles in diverse processes such as development, metabolism, and tumor progression. The heterogeneity of Drosophila immune cells (hemocytes) remains an open question. Using bulk RNA sequencing, we find that the hemocytes display distinct features in the embryo, a closed and rapidly developing system, compared to the larva, which is exposed to environmental and metabolic challenges. Through single-cell RNA sequencing, we identify fourteen hemocyte clusters present in unchallenged larvae and associated with distinct processes, e.g., proliferation, phagocytosis, metabolic homeostasis, and humoral response. Finally, we characterize the changes occurring in the hemocyte clusters upon wasp infestation, which triggers the differentiation of a novel hemocyte type, the lamellocyte. This first molecular atlas of hemocytes provides insights and paves the way to study the biology of the Drosophila immune cells in physiological and pathological conditions.
Collapse
Affiliation(s)
- Pierre B Cattenoz
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Rosy Sakr
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Alexia Pavlidaki
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Claude Delaporte
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Andrea Riba
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Nacho Molina
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| | - Nivedita Hariharan
- Institute for Stem Cell Science and Regenerative Medicine (inStem)BangaloreIndia
- The University of Trans‐disciplinary Health Sciences and TechnologyBangaloreIndia
| | - Tina Mukherjee
- Institute for Stem Cell Science and Regenerative Medicine (inStem)BangaloreIndia
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et CellulaireIllkirchFrance
- Centre National de la Recherche ScientifiqueUMR7104IllkirchFrance
- Institut National de la Santé et de la Recherche Médicale, U1258IllkirchFrance
- Université de StrasbourgIllkirchFrance
| |
Collapse
|
31
|
Esencan E, Kallen A, Zhang M, Seli E. Translational activation of maternally derived mRNAs in oocytes and early embryos and the role of embryonic poly(A) binding protein (EPAB). Biol Reprod 2020; 100:1147-1157. [PMID: 30806655 DOI: 10.1093/biolre/ioz034] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/23/2019] [Accepted: 02/23/2019] [Indexed: 12/20/2022] Open
Abstract
Transcription ceases upon stimulation of oocyte maturation and gene expression during oocyte maturation, fertilization, and early cleavage relies on translational activation of maternally derived mRNAs. Two key mechanisms that mediate translation of mRNAs in oocytes have been described in detail: cytoplasmic polyadenylation-dependent and -independent. Both of these mechanisms utilize specific protein complexes that interact with cis-acting sequences located on 3'-untranslated region (3'-UTR), and both involve embryonic poly(A) binding protein (EPAB), the predominant poly(A) binding protein during early development. While mechanistic details of these pathways have primarily been elucidated using the Xenopus model, their roles are conserved in mammals and targeted disruption of key regulators in mouse results in female infertility. Here, we provide a detailed account of the molecular mechanisms involved in translational activation during oocyte and early embryo development, and the role of EPAB in this process.
Collapse
Affiliation(s)
- Ecem Esencan
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Amanda Kallen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Man Zhang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| | - Emre Seli
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut, USA
| |
Collapse
|
32
|
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
| |
Collapse
|
33
|
Walther M, Schrahn S, Krauss V, Lein S, Kessler J, Jenuwein T, Reuter G. Heterochromatin formation in Drosophila requires genome-wide histone deacetylation in cleavage chromatin before mid-blastula transition in early embryogenesis. Chromosoma 2020; 129:83-98. [PMID: 31950239 PMCID: PMC7021753 DOI: 10.1007/s00412-020-00732-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 02/05/2023]
Abstract
Su(var) mutations define epigenetic factors controlling heterochromatin formation and gene silencing in Drosophila. Here, we identify SU(VAR)2-1 as a novel chromatin regulator that directs global histone deacetylation during the transition of cleavage chromatin into somatic blastoderm chromatin in early embryogenesis. SU(VAR)2-1 is heterochromatin-associated in blastoderm nuclei but not in later stages of development. In larval polytene chromosomes, SU(VAR)2-1 is a band-specific protein. SU(VAR)2-1 directs global histone deacetylation by recruiting the histone deacetylase RPD3. In Su(var)2-1 mutants H3K9, H3K27, H4K8 and H4K16 acetylation shows elevated levels genome-wide and heterochromatin displays aberrant histone hyper-acetylation. Whereas H3K9me2- and HP1a-binding appears unaltered, the heterochromatin-specific H3K9me2S10ph composite mark is impaired in heterochromatic chromocenters of larval salivary polytene chromosomes. SU(VAR)2-1 contains an NRF1/EWG domain and a C2HC zinc-finger motif. Our study identifies SU(VAR)2-1 as a dosage-dependent, heterochromatin-initiating SU(VAR) factor, where the SU(VAR)2-1-mediated control of genome-wide histone deacetylation after cleavage and before mid-blastula transition (pre-MBT) is required to enable heterochromatin formation.
Collapse
Affiliation(s)
- Matthias Walther
- Developmental Genetics, Institute of Biology, Martin Luther University Halle, Weinbergweg 10, 06120, Halle/S., Germany
- Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Sandy Schrahn
- Developmental Genetics, Institute of Biology, Martin Luther University Halle, Weinbergweg 10, 06120, Halle/S., Germany
| | - Veiko Krauss
- Cluster of Excellence in Plant Science (CEPLAS), University of Cologne, Biocenter, 50674, Cologne, Germany
| | - Sandro Lein
- Developmental Genetics, Institute of Biology, Martin Luther University Halle, Weinbergweg 10, 06120, Halle/S., Germany
| | - Jeannette Kessler
- Developmental Genetics, Institute of Biology, Martin Luther University Halle, Weinbergweg 10, 06120, Halle/S., Germany
| | - Thomas Jenuwein
- Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Gunter Reuter
- Developmental Genetics, Institute of Biology, Martin Luther University Halle, Weinbergweg 10, 06120, Halle/S., Germany.
| |
Collapse
|
34
|
Abstract
Drosophila melanogaster embryos develop initially as a syncytium of totipotent nuclei and subsequently, once cellularized, undergo morphogenetic movements associated with gastrulation to generate the three somatic germ layers of the embryo: mesoderm, ectoderm, and endoderm. In this chapter, we focus on the first phase of gastrulation in Drosophila involving patterning of early embryos when cells differentiate their gene expression programs. This patterning process requires coordination of multiple developmental processes including genome reprogramming at the maternal-to-zygotic transition, combinatorial action of transcription factors to support distinct gene expression, and dynamic feedback between this genetic patterning by transcription factors and changes in cell morphology. We discuss the gene regulatory programs acting during patterning to specify the three germ layers, which involve the regulation of spatiotemporal gene expression coupled to physical tissue morphogenesis.
Collapse
Affiliation(s)
- Angelike Stathopoulos
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, United States.
| | - Susan Newcomb
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| |
Collapse
|
35
|
Harpprecht L, Baldi S, Schauer T, Schmidt A, Bange T, Robles MS, Kremmer E, Imhof A, Becker PB. A Drosophila cell-free system that senses DNA breaks and triggers phosphorylation signalling. Nucleic Acids Res 2019; 47:7444-7459. [PMID: 31147711 PMCID: PMC6698661 DOI: 10.1093/nar/gkz473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/16/2019] [Indexed: 11/23/2022] Open
Abstract
Preblastoderm Drosophila embryo development is characterized by fast cycles of nuclear divisions. Extracts from these embryos can be used to reconstitute complex chromatin with high efficiency. We now discovered that this chromatin assembly system contains activities that recognize unprotected DNA ends and signal DNA damage through phosphorylation. DNA ends are initially bound by Ku and MRN complexes. Within minutes, the phosphorylation of H2A.V (homologous to γH2A.X) initiates from DNA breaks and spreads over tens of thousands DNA base pairs. The γH2A.V phosphorylation remains tightly associated with the damaged DNA and does not spread to undamaged DNA in the same reaction. This first observation of long-range γH2A.X spreading along damaged chromatin in an in vitro system provides a unique opportunity for mechanistic dissection. Upon further incubation, DNA ends are rendered single-stranded and bound by the RPA complex. Phosphoproteome analyses reveal damage-dependent phosphorylation of numerous DNA-end-associated proteins including Ku70, RPA2, CHRAC16, the exonuclease Rrp1 and the telomer capping complex. Phosphorylation of spindle assembly checkpoint components and of microtubule-associated proteins required for centrosome integrity suggests this cell-free system recapitulates processes involved in the regulated elimination of fatally damaged syncytial nuclei.
Collapse
Affiliation(s)
- Lisa Harpprecht
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Sandro Baldi
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
| | - Tamas Schauer
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Bioinformatics Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Andreas Schmidt
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Tanja Bange
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Maria S Robles
- Institute of Medical Psychology, LMU Munich, 80336 Munich, Germany
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, German Research Center for Environmental Health, 81377 Munich, Germany
| | - Axel Imhof
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- Protein Analysis Unit, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Peter B Becker
- Molecular Biology Division, Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich, LMU Munich, 81377 Munich, Germany
- To whom correspondence should be addressed. Tel: +49 89 2180 75427; Fax: +49 89 2180 75425;
| |
Collapse
|
36
|
Bonnet J, Lindeboom RGH, Pokrovsky D, Stricker G, Çelik MH, Rupp RAW, Gagneur J, Vermeulen M, Imhof A, Müller J. Quantification of Proteins and Histone Marks in Drosophila Embryos Reveals Stoichiometric Relationships Impacting Chromatin Regulation. Dev Cell 2019; 51:632-644.e6. [PMID: 31630981 DOI: 10.1016/j.devcel.2019.09.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/09/2019] [Accepted: 09/16/2019] [Indexed: 10/25/2022]
Abstract
Gene transcription in eukaryotes is regulated through dynamic interactions of a variety of different proteins with DNA in the context of chromatin. Here, we used mass spectrometry for absolute quantification of the nuclear proteome and methyl marks on selected lysine residues in histone H3 during two stages of Drosophila embryogenesis. These analyses provide comprehensive information about the absolute copy number of several thousand proteins and reveal unexpected relationships between the abundance of histone-modifying and -binding proteins and the chromatin landscape that they generate and interact with. For some histone modifications, the levels in Drosophila embryos are substantially different from those previously reported in tissue culture cells. Genome-wide profiling of H3K27 methylation during developmental progression and in animals with reduced PRC2 levels illustrates how mass spectrometry can be used for quantitatively describing and comparing chromatin states. Together, these data provide a foundation toward a quantitative understanding of gene regulation in Drosophila.
Collapse
Affiliation(s)
- Jacques Bonnet
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Rik G H Lindeboom
- Radboud Institute for Molecular Life Sciences, Oncode Institute, Department of Molecular Biology, Radboud University, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands
| | - Daniil Pokrovsky
- Institute for Molecular Biology, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany; Protein Analysis Unit, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Georg Stricker
- Department of Informatics, Technical University of Munich, Boltzmannstr. 3, 85748 Garching, Germany
| | - Muhammed Hasan Çelik
- Department of Informatics, Technical University of Munich, Boltzmannstr. 3, 85748 Garching, Germany
| | - Ralph A W Rupp
- Institute for Molecular Biology, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany
| | - Julien Gagneur
- Department of Informatics, Technical University of Munich, Boltzmannstr. 3, 85748 Garching, Germany
| | - Michiel Vermeulen
- Radboud Institute for Molecular Life Sciences, Oncode Institute, Department of Molecular Biology, Radboud University, Geert Grooteplein 28, 6525 GA Nijmegen, the Netherlands.
| | - Axel Imhof
- Protein Analysis Unit, BioMedical Center, Faculty of Medicine, Ludwig-Maximilians-University Munich, Großhadernerstr. 9, 82152 Martinsried, Germany.
| | - Jürg Müller
- Max-Planck Institute of Biochemistry, Laboratory of Chromatin Biology, Am Klopferspitz 18, 82152 Martinsried, Germany.
| |
Collapse
|
37
|
Mutlu B, Chen HM, Gutnik S, Hall DH, Keppler-Ross S, Mango SE. Distinct functions and temporal regulation of methylated histone H3 during early embryogenesis. Development 2019; 146:dev174516. [PMID: 31540912 PMCID: PMC6803369 DOI: 10.1242/dev.174516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 09/09/2019] [Indexed: 01/25/2023]
Abstract
During the first hours of embryogenesis, formation of higher-order heterochromatin coincides with the loss of developmental potential. Here, we examine the relationship between these two events, and we probe the processes that contribute to the timing of their onset. Mutations that disrupt histone H3 lysine 9 (H3K9) methyltransferases reveal that the methyltransferase MET-2 helps terminate developmental plasticity, through mono- and di-methylation of H3K9 (me1/me2), and promotes heterochromatin formation, through H3K9me3. Although loss of H3K9me3 perturbs formation of higher-order heterochromatin, embryos are still able to terminate plasticity, indicating that the two processes can be uncoupled. Methylated H3K9 appears gradually in developing C. elegans embryos and depends on nuclear localization of MET-2. We find that the timing of H3K9me2 and nuclear MET-2 is sensitive to rapid cell cycles, but not to zygotic genome activation or cell counting. These data reveal distinct roles for different H3K9 methylation states in the generation of heterochromatin and loss of developmental plasticity by MET-2, and identify the cell cycle as a crucial parameter of MET-2 regulation.
Collapse
Affiliation(s)
- Beste Mutlu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Huei-Mei Chen
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Silvia Gutnik
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - David H Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | - Susan E Mango
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| |
Collapse
|
38
|
Hu X, Eastman AE, Guo S. Cell cycle dynamics in the reprogramming of cellular identity. FEBS Lett 2019; 593:2840-2852. [PMID: 31562821 DOI: 10.1002/1873-3468.13625] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 12/13/2022]
Abstract
Reprogramming of cellular identity is fundamentally at odds with replication of the genome: cell fate reprogramming requires complex multidimensional epigenomic changes, whereas genome replication demands fidelity. In this review, we discuss how the pace of the genome's replication and cell cycle influences the way daughter cells take on their identity. We highlight several biochemical processes that are pertinent to cell fate control, whose propagation into the daughter cells should be governed by more complex mechanisms than simple templated replication. With this mindset, we summarize multiple scenarios where rapid cell cycle could interfere with cell fate copying and promote cell fate reprogramming. Prominent examples of cell fate regulation by specific cell cycle phases are also discussed. Overall, there is much to be learned regarding the relationship between cell fate reprogramming and cell cycle control. Harnessing cell cycle dynamics could greatly facilitate the derivation of desired cell types.
Collapse
Affiliation(s)
- Xiao Hu
- Department of Cell Biology, Yale University, New Haven, CT, USA.,Yale Stem Cell Center, Yale University, New Haven, CT, USA
| | - Anna E Eastman
- Department of Cell Biology, Yale University, New Haven, CT, USA.,Yale Stem Cell Center, Yale University, New Haven, CT, USA
| | - Shangqin Guo
- Department of Cell Biology, Yale University, New Haven, CT, USA.,Yale Stem Cell Center, Yale University, New Haven, CT, USA
| |
Collapse
|
39
|
Chari S, Wilky H, Govindan J, Amodeo AA. Histone concentration regulates the cell cycle and transcription in early development. Development 2019; 146:dev.177402. [PMID: 31511251 DOI: 10.1242/dev.177402] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022]
Abstract
The early embryos of many animals, including flies, fish and frogs, have unusually rapid cell cycles and delayed onset of transcription. These divisions are dependent on maternally supplied RNAs and proteins including histones. Previous work suggests that the pool size of maternally provided histones can alter the timing of zygotic genome activation (ZGA) in frogs and fish. Here, we examine the effects of under- and overexpression of maternal histones in Drosophila embryogenesis. Decreasing histone concentration advances zygotic transcription, cell cycle elongation, Chk1 activation and gastrulation. Conversely, increasing histone concentration delays transcription and results in an additional nuclear cycle before gastrulation. Numerous zygotic transcripts are sensitive to histone concentration, and the promoters of histone-sensitive genes are associated with specific chromatin features linked to increased histone turnover. These include enrichment of the pioneer transcription factor Zelda, and lack of SIN3A and associated histone deacetylases. Our findings uncover a crucial regulatory role for histone concentrations in ZGA of Drosophila.
Collapse
Affiliation(s)
- Sudarshan Chari
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Henry Wilky
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jayalakshmi Govindan
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Amanda A Amodeo
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
40
|
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.
Collapse
|
41
|
Kwasnieski JC, Orr-Weaver TL, Bartel DP. Early genome activation in Drosophila is extensive with an initial tendency for aborted transcripts and retained introns. Genome Res 2019; 29:1188-1197. [PMID: 31235656 PMCID: PMC6633261 DOI: 10.1101/gr.242164.118] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 05/08/2019] [Indexed: 01/02/2023]
Abstract
Control of metazoan embryogenesis shifts from maternal to zygotic gene products as the zygotic genome becomes transcriptionally activated. In Drosophila, zygotic genome activation (ZGA) has been thought to occur in two phases, starting with a minor wave, in which a small number of genes become expressed, and progressing to the major wave, in which many more genes are activated. However, technical challenges have hampered the identification of early transcripts or obscured the onset of their transcription. Here, we develop an approach to isolate transcribed mRNAs and apply it over the course of Drosophila early genome activation. Our results increase by 10-fold the genes reported to be activated during what has been thought of as the minor wave and show that early genome activation is continuous and gradual. Transposable-element mRNAs are also produced, but discontinuously. Genes transcribed in the early and middle part of ZGA are short with few if any introns, and their transcripts are frequently aborted and tend to have retained introns, suggesting that inefficient splicing as well as rapid cell divisions constrain the lengths of early transcripts.
Collapse
Affiliation(s)
- Jamie C Kwasnieski
- Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
| | - Terry L Orr-Weaver
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
| | - David P Bartel
- Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
| |
Collapse
|
42
|
Seller CA, Cho CY, O'Farrell PH. Rapid embryonic cell cycles defer the establishment of heterochromatin by Eggless/SetDB1 in Drosophila. Genes Dev 2019; 33:403-417. [PMID: 30808658 PMCID: PMC6446540 DOI: 10.1101/gad.321646.118] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/14/2019] [Indexed: 12/15/2022]
Abstract
Acquisition of chromatin modifications during embryogenesis distinguishes different regions of an initially naïve genome. In many organisms, repetitive DNA is packaged into constitutive heterochromatin that is marked by di/trimethylation of histone H3K9 and the associated protein HP1a. These modifications enforce the unique epigenetic properties of heterochromatin. However, in the early Drosophila melanogaster embryo, the heterochromatin lacks these modifications, which appear only later, when rapid embryonic cell cycles slow down at the midblastula transition (MBT). Here we focus on the initial steps restoring heterochromatic modifications in the embryo. We describe the JabbaTrap, a technique for inactivating maternally provided proteins in embryos. Using the JabbaTrap, we reveal a major requirement for the methyltransferase Eggless/SetDB1 in the establishment of heterochromatin. In contrast, other methyltransferases contribute minimally. Live imaging reveals that endogenous Eggless gradually accumulates on chromatin in interphase but then dissociates in mitosis, and its accumulation must restart in the next cell cycle. Cell cycle slowing as the embryo approaches the MBT permits increasing accumulation and action of Eggless at its targets. Experimental manipulation of interphase duration shows that cell cycle speed regulates Eggless. We propose that developmental slowing of the cell cycle times embryonic heterochromatin formation.
Collapse
Affiliation(s)
- Charles A Seller
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
| | - Chun-Yi Cho
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
| | - Patrick H O'Farrell
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA
| |
Collapse
|
43
|
Developmental Control of the Cell Cycle: Insights from Caenorhabditis elegans. Genetics 2019; 211:797-829. [PMID: 30846544 PMCID: PMC6404260 DOI: 10.1534/genetics.118.301643] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
During animal development, a single fertilized egg forms a complete organism with tens to trillions of cells that encompass a large variety of cell types. Cell cycle regulation is therefore at the center of development and needs to be carried out in close coordination with cell differentiation, migration, and death, as well as tissue formation, morphogenesis, and homeostasis. The timing and frequency of cell divisions are controlled by complex combinations of external and cell-intrinsic signals that vary throughout development. Insight into how such controls determine in vivo cell division patterns has come from studies in various genetic model systems. The nematode Caenorhabditis elegans has only about 1000 somatic cells and approximately twice as many germ cells in the adult hermaphrodite. Despite the relatively small number of cells, C. elegans has diverse tissues, including intestine, nerves, striated and smooth muscle, and skin. C. elegans is unique as a model organism for studies of the cell cycle because the somatic cell lineage is invariant. Somatic cells divide at set times during development to produce daughter cells that adopt reproducible developmental fates. Studies in C. elegans have allowed the identification of conserved cell cycle regulators and provided insights into how cell cycle regulation varies between tissues. In this review, we focus on the regulation of the cell cycle in the context of C. elegans development, with reference to other systems, with the goal of better understanding how cell cycle regulation is linked to animal development in general.
Collapse
|
44
|
Chen L, Barnett RE, Horstmann M, Bamberger V, Heberle L, Krebs N, Colbourne JK, Gómez R, Weiss LC. Mitotic activity patterns and cytoskeletal changes throughout the progression of diapause developmental program in Daphnia. BMC Cell Biol 2018; 19:30. [PMID: 30594127 PMCID: PMC6310958 DOI: 10.1186/s12860-018-0181-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/13/2018] [Indexed: 01/03/2023] Open
Abstract
Background Diapause is a form of dormancy that is genetically predetermined to allow animals to overcome harsh environmental conditions. It is induced by predictive environmental cues bringing cellular activity levels into a state of suspended animation. Entering diapause requires organismal, molecular and cellular adaptation to severely reduced energy flows. Cells must therefore have evolved strategies that prepare them for periods with limited metabolic resources. However, changes that occur on the (sub-)cellular level have not been thoroughly described. Results We investigated mitotic activity and we monitored cytoskeletal network changes in successive stages of diapausing and non-diapausing Daphnia magna embryos using (immuno-)fluorescent labeling. We find that embryos destined to diapause show a delayed and 2.5x slower mitotic activity in comparison to continuously developing embryos. Development is halted when D. magna embryos reach ~ 3500 cells, whereupon mitotic activity is absent and cytoskeletal components are severely reduced, rendering diapause cells compact and condensed. Conclusion In the initiation phase of diapause, the slower cell division rate points to prolonged interphase duration, preparing the cells for diapause maintenance. During diapause, cytoskeletal depletion and cellular condensation may be a means to save energy resources. Our data provide insights into the sub-cellular change of diapause in Daphnia.
Collapse
Affiliation(s)
- Luxi Chen
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany
| | - Rosemary E Barnett
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Martin Horstmann
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany
| | - Verena Bamberger
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany
| | - Lea Heberle
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany
| | - Nina Krebs
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany
| | - John K Colbourne
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Rocío Gómez
- Departamento de Biología. Facultad de Ciencias, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Linda C Weiss
- Department of Animal Ecology, Evolution and Biodiversity, Ruhr-University Bochum, NDEF 05/751, Universitaetsstrasse 150, 44780, Bochum, Germany.
| |
Collapse
|
45
|
Hamm DC, Harrison MM. Regulatory principles governing the maternal-to-zygotic transition: insights from Drosophila melanogaster. Open Biol 2018; 8:180183. [PMID: 30977698 PMCID: PMC6303782 DOI: 10.1098/rsob.180183] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022] Open
Abstract
The onset of metazoan development requires that two terminally differentiated germ cells, a sperm and an oocyte, become reprogrammed to the totipotent embryo, which can subsequently give rise to all the cell types of the adult organism. In nearly all animals, maternal gene products regulate the initial events of embryogenesis while the zygotic genome remains transcriptionally silent. Developmental control is then passed from mother to zygote through a process known as the maternal-to-zygotic transition (MZT). The MZT comprises an intimately connected set of molecular events that mediate degradation of maternally deposited mRNAs and transcriptional activation of the zygotic genome. This essential developmental transition is conserved among metazoans but is perhaps best understood in the fruit fly, Drosophila melanogaster. In this article, we will review our understanding of the events that drive the MZT in Drosophila embryos and highlight parallel mechanisms driving this transition in other animals.
Collapse
Affiliation(s)
| | - Melissa M. Harrison
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| |
Collapse
|
46
|
Johnson MR, Stephenson RA, Ghaemmaghami S, Welte MA. Developmentally regulated H2Av buffering via dynamic sequestration to lipid droplets in Drosophila embryos. eLife 2018; 7:36021. [PMID: 30044219 PMCID: PMC6089599 DOI: 10.7554/elife.36021] [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: 02/16/2018] [Accepted: 07/24/2018] [Indexed: 12/23/2022] Open
Abstract
Regulating nuclear histone balance is essential for survival, yet in early Drosophila melanogaster embryos many regulatory strategies employed in somatic cells are unavailable. Previous work had suggested that lipid droplets (LDs) buffer nuclear accumulation of the histone variant H2Av. Here, we elucidate the buffering mechanism and demonstrate that it is developmentally controlled. Using live imaging, we find that H2Av continuously exchanges between LDs. Our data suggest that the major driving force for H2Av accumulation in nuclei is H2Av abundance in the cytoplasm and that LD binding slows nuclear import kinetically, by limiting this cytoplasmic pool. Nuclear H2Av accumulation is indeed inversely regulated by overall buffering capacity. Histone exchange between LDs abruptly ceases during the midblastula transition, presumably to allow canonical regulatory mechanisms to take over. These findings provide a mechanistic basis for the emerging role of LDs as regulators of protein homeostasis and demonstrate that LDs can control developmental progression.
Collapse
Affiliation(s)
| | | | - Sina Ghaemmaghami
- Department of Biology, University of Rochester, Rochester, United States
| | | |
Collapse
|
47
|
Seller CA, O’Farrell PH. Rif1 prolongs the embryonic S phase at the Drosophila mid-blastula transition. PLoS Biol 2018; 16:e2005687. [PMID: 29746464 PMCID: PMC5963817 DOI: 10.1371/journal.pbio.2005687] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/22/2018] [Accepted: 04/23/2018] [Indexed: 01/09/2023] Open
Abstract
In preparation for dramatic morphogenetic events of gastrulation, rapid embryonic cell cycles slow at the mid-blastula transition (MBT). In Drosophila melanogaster embryos, down-regulation of cyclin-dependent kinase 1 (Cdk1) activity initiates this slowing by delaying replication of heterochromatic satellite sequences and extending S phase. We found that Cdk1 activity inhibited the chromatin association of Rap1 interacting factor 1 (Rif1), a candidate repressor of replication. Furthermore, Rif1 bound selectively to satellite sequences following Cdk1 down-regulation at the MBT. In the next S phase, Rif1 dissociated from different satellites in an orderly schedule that anticipated their replication. Rif1 lacking potential phosphorylation sites failed to dissociate and dominantly prevented completion of replication. Loss of Rif1 in mutant embryos shortened the post-MBT S phase and rescued embryonic cell cycles disrupted by depletion of the S phase–promoting kinase, cell division cycle 7 (Cdc7). Our work shows that Rif1 and S phase kinases compose a replication timer controlling first the developmental onset of late replication and then the precise schedule of replication within S phase. In addition, we describe how onset of late replication fits into the progressive maturation of heterochromatin during development. Cells divide rapidly in the early embryos of most animals. However, during a conserved period of development known as the mid-blastula transition (MBT), the cell cycle slows down dramatically. In Drosophila embryos, genome duplication abruptly slows to initiate this cell cycle prolongation. This is achieved through the onset of late replication, a well-recognized phenomenon in which specific sequences of the genome await replication until long after other sequences have finished. Even though this temporal program of replication is a major determinant of the duration of S phase, the factors involved in this process remain unknown. Here, we use genetics and real-time microscopy to visualize replication in developing fly embryos and show that the protein Rap1 interacting factor 1 (Rif1) mediates the introduction of late replication at the MBT. We find that at this stage, Rif1 binds to and selectively delays the replication of large blocks of repetitive DNA known as satellite sequences. During the rapid cell cycles before the MBT, we show that the cyclin-dependent kinase 1 (Cdk1) prevents Rif1 from slowing down DNA replication by driving its removal from the chromatin. The developmental down-regulation of Cdk1 at the MBT allows Rif1 to associate with the satellite sequences and initiate cell cycle slowing. Our work provides new insights into the temporal programming of S phase and into the embryonic origin of late replication.
Collapse
Affiliation(s)
- Charles A. Seller
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Patrick H. O’Farrell
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
| |
Collapse
|
48
|
Schmidt A, Grosshans J. Dynamics of cortical domains in early Drosophila development. J Cell Sci 2018; 131:131/7/jcs212795. [DOI: 10.1242/jcs.212795] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT
Underlying the plasma membrane of eukaryotic cells is an actin cortex that includes actin filaments and associated proteins. A special feature of all polarized and epithelial cells are cortical domains, each of which is characterized by specific sets of proteins. Typically, an epithelial cell contains apical, subapical, lateral and basal domains. The domain-specific protein sets contain evolutionarily conserved proteins, as well as cell-type-specific factors. Among the conserved proteins are, the Par proteins, Crumbs complex and the lateral proteins Scribbled and Discs large 1. Organization of the plasma membrane into cortical domains is dynamic and depends on cell type, differentiation and developmental stage. The dynamics of cortical organization is strikingly visible in early Drosophila embryos, which increase the number of distinct cortical domains from one, during the pre-blastoderm stage, to two in syncytial blastoderm embryos, before finally acquiring the four domains that are typical for epithelial cells during cellularization. In this Review, we will describe the dynamics of cortical organization in early Drosophila embryos and discuss the processes and mechanisms underlying cortical remodeling.
Collapse
Affiliation(s)
- Anja Schmidt
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, 37077 Göttingen, Germany
| | - Jörg Grosshans
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, 37077 Göttingen, Germany
| |
Collapse
|
49
|
Biochemical Fractionation of Time-Resolved Drosophila Embryos Reveals Similar Transcriptomic Alterations in Replication Checkpoint and Histone mRNA Processing Mutants. J Mol Biol 2017; 429:3264-3279. [DOI: 10.1016/j.jmb.2017.01.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 11/22/2022]
|
50
|
Chk1 Inhibition of the Replication Factor Drf1 Guarantees Cell-Cycle Elongation at the Xenopus laevis Mid-blastula Transition. Dev Cell 2017; 42:82-96.e3. [PMID: 28697335 PMCID: PMC5505860 DOI: 10.1016/j.devcel.2017.06.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 04/19/2017] [Accepted: 06/07/2017] [Indexed: 12/21/2022]
Abstract
The early cell divisions of many metazoan embryos are rapid and occur in the near absence of transcription. At the mid-blastula transition (MBT), the cell cycle elongates and several processes become established including the onset of bulk transcription and cell-cycle checkpoints. How these events are timed and coordinated is poorly understood. Here we show in Xenopus laevis that developmental activation of the checkpoint kinase Chk1 at the MBT results in the SCFβ-TRCP-dependent degradation of a limiting replication initiation factor Drf1. Inhibition of Drf1 is the primary mechanism by which Chk1 blocks cell-cycle progression in the early embryo and is an essential function of Chk1 at the blastula-to-gastrula stage of development. This study defines the downregulation of Drf1 as an important mechanism to coordinate the lengthening of the cell cycle and subsequent developmental processes. Activation of Chk1 at the Xenopus MBT results in the degradation of Drf1 Drf1 degradation is SCFβ-TRCP dependent Chk1 blocks the cell cycle in the early embryo through inhibition of Drf1 Inhibition of Drf1 is an essential function of Chk1 during gastrulation
Collapse
|