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Awad S, Skipper W, Vostrejs W, Ozorowski K, Min K, Pfuhler L, Mehta D, Cooke A. The YBX3 RNA-binding protein posttranscriptionally controls SLC1A5 mRNA in proliferating and differentiating skeletal muscle cells. J Biol Chem 2024; 300:105602. [PMID: 38159852 PMCID: PMC10837625 DOI: 10.1016/j.jbc.2023.105602] [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: 07/29/2023] [Revised: 11/22/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024] Open
Abstract
In humans, skeletal muscles comprise nearly 40% of total body mass, which is maintained throughout adulthood by a balance of muscle protein synthesis and breakdown. Cellular amino acid (AA) levels are critical for these processes, and mammalian cells contain transporter proteins that import AAs to maintain homeostasis. Until recently, the control of transporter regulation has largely been studied at the transcriptional and posttranslational levels. However, here, we report that the RNA-binding protein YBX3 is critical to sustain intracellular AAs in mouse skeletal muscle cells, which aligns with our recent findings in human cells. We find that YBX3 directly binds the solute carrier (SLC)1A5 AA transporter messenger (m)RNA to posttranscriptionally control SLC1A5 expression during skeletal muscle cell differentiation. YBX3 regulation of SLC1A5 requires the 3' UTR. Additionally, intracellular AAs transported by SLC1A5, either directly or indirectly through coupling to other transporters, are specifically reduced when YBX3 is depleted. Further, we find that reduction of the YBX3 protein reduces proliferation and impairs differentiation in skeletal muscle cells, and that YBX3 and SLC1A5 protein expression increase substantially during skeletal muscle differentiation, independently of their respective mRNA levels. Taken together, our findings suggest that YBX3 regulates AA transport in skeletal muscle cells, and that its expression is critical to maintain skeletal muscle cell proliferation and differentiation.
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Affiliation(s)
- Silina Awad
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | - William Skipper
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | - William Vostrejs
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | | | - Kristen Min
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | - Liva Pfuhler
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | - Darshan Mehta
- Biology Department, Haverford College, Haverford, Pennsylvania, USA
| | - Amy Cooke
- Biology Department, Haverford College, Haverford, Pennsylvania, USA.
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2
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Moritz L, Schon SB, Rabbani M, Sheng Y, Agrawal R, Glass-Klaiber J, Sultan C, Camarillo JM, Clements J, Baldwin MR, Diehl AG, Boyle AP, O'Brien PJ, Ragunathan K, Hu YC, Kelleher NL, Nandakumar J, Li JZ, Orwig KE, Redding S, Hammoud SS. Sperm chromatin structure and reproductive fitness are altered by substitution of a single amino acid in mouse protamine 1. Nat Struct Mol Biol 2023; 30:1077-1091. [PMID: 37460896 PMCID: PMC10833441 DOI: 10.1038/s41594-023-01033-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 06/12/2023] [Indexed: 08/11/2023]
Abstract
Conventional dogma presumes that protamine-mediated DNA compaction in sperm is achieved by electrostatic interactions between DNA and the arginine-rich core of protamines. Phylogenetic analysis reveals several non-arginine residues conserved within, but not across species. The significance of these residues and their post-translational modifications are poorly understood. Here, we investigated the role of K49, a rodent-specific lysine residue in protamine 1 (P1) that is acetylated early in spermiogenesis and retained in sperm. In sperm, alanine substitution (P1(K49A)) decreases sperm motility and male fertility-defects that are not rescued by arginine substitution (P1(K49R)). In zygotes, P1(K49A) leads to premature male pronuclear decompaction, altered DNA replication, and embryonic arrest. In vitro, P1(K49A) decreases protamine-DNA binding and alters DNA compaction and decompaction kinetics. Hence, a single amino acid substitution outside the P1 arginine core is sufficient to profoundly alter protein function and developmental outcomes, suggesting that protamine non-arginine residues are essential for reproductive fitness.
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Affiliation(s)
- Lindsay Moritz
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Samantha B Schon
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
| | - Mashiat Rabbani
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Yi Sheng
- Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ritvija Agrawal
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Juniper Glass-Klaiber
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Caleb Sultan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Jeannie M Camarillo
- Departments of Chemistry, Molecular Biosciences, and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, IL, USA
| | - Jourdan Clements
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Michael R Baldwin
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Adam G Diehl
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Alan P Boyle
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Patrick J O'Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | | | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Neil L Kelleher
- Departments of Chemistry, Molecular Biosciences, and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, IL, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jun Z Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Kyle E Orwig
- Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sy Redding
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Saher Sue Hammoud
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA.
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA.
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA.
- Department of Urology, University of Michigan, Ann Arbor, MI, USA.
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3
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Cridland JM, Contino CE, Begun DJ. Selection and geography shape male reproductive tract transcriptomes in Drosophila melanogaster. Genetics 2023; 224:iyad034. [PMID: 36869688 PMCID: PMC10474930 DOI: 10.1093/genetics/iyad034] [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: 01/25/2023] [Revised: 01/25/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Transcriptome analysis of several animal clades suggests that male reproductive tract gene expression evolves quickly. However, the factors influencing the abundance and distribution of within-species variation, the ultimate source of interspecific divergence, are poorly known. Drosophila melanogaster, an ancestrally African species that has recently spread throughout the world and colonized the Americas in the last roughly 100 years, exhibits phenotypic and genetic latitudinal clines on multiple continents, consistent with a role for spatially varying selection in shaping its biology. Nevertheless, geographic expression variation in the Americas is poorly described, as is its relationship to African expression variation. Here, we investigate these issues through the analysis of two male reproductive tissue transcriptomes [testis and accessory gland (AG)] in samples from Maine (USA), Panama, and Zambia. We find dramatic differences between these tissues in differential expression between Maine and Panama, with the accessory glands exhibiting abundant expression differentiation and the testis exhibiting very little. Latitudinal expression differentiation appears to be influenced by the selection of Panama expression phenotypes. While the testis shows little latitudinal expression differentiation, it exhibits much greater differentiation than the accessory gland in Zambia vs American population comparisons. Expression differentiation for both tissues is non-randomly distributed across the genome on a chromosome arm scale. Interspecific expression divergence between D. melanogaster and D. simulans is discordant with rates of differentiation between D. melanogaster populations. Strongly heterogeneous expression differentiation across tissues and timescales suggests a complex evolutionary process involving major temporal changes in the way selection influences expression evolution in these organs.
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Affiliation(s)
- Julie M Cridland
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
| | - Colin E Contino
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
| | - David J Begun
- Department of Evolution and Ecology, University of California-Davis, Davis, CA 95616, USA
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4
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Zhelankin AV, Iulmetova LN, Ahmetov II, Generozov EV, Sharova EI. Diversity and Differential Expression of MicroRNAs in the Human Skeletal Muscle with Distinct Fiber Type Composition. Life (Basel) 2023; 13:659. [PMID: 36983815 PMCID: PMC10056610 DOI: 10.3390/life13030659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023] Open
Abstract
The ratio of fast- and slow-twitch fibers in human skeletal muscle is variable and largely determined by genetic factors. In this study, we investigated the contribution of microRNA (miRNA) in skeletal muscle fiber type composition. The study involved biopsy samples of the vastus lateralis muscle from 24 male participants with distinct fiber type ratios. The miRNA study included samples from five endurance athletes and five power athletes with the predominance of slow-twitch (61.6-72.8%) and fast-twitch (69.3-80.7%) fibers, respectively. Total and small RNA were extracted from tissue samples. Total RNA sequencing (N = 24) revealed 352 differentially expressed genes between the groups with the predominance of fast- and slow-twitch muscle fibers. Small RNA sequencing showed upregulation of miR-206, miR-501-3p and miR-185-5p, and downregulation of miR-499a-5p and miR-208-5p in the group of power athletes with fast-twitch fiber predominance. Two miRtronic miRNAs, miR-208b-3p and miR-499a-5p, had strong correlations in expression with their host genes (MYH7 and MYH7B, respectively). Correlations between the expression of miRNAs and their experimentally validated messenger RNA (mRNA) targets were calculated, and 11 miRNA-mRNA interactions with strong negative correlations were identified. Two of them belonged to miR-208b-3p and miR-499a-5p, indicating their regulatory links with the expression of CDKN1A and FOXO4, respectively.
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Affiliation(s)
- Andrey V. Zhelankin
- Department of Molecular Biology and Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Liliia N. Iulmetova
- Department of Molecular Biology and Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Ildus I. Ahmetov
- Department of Molecular Biology and Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 5AF, UK
| | - Eduard V. Generozov
- Department of Molecular Biology and Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
| | - Elena I. Sharova
- Department of Molecular Biology and Genetics, Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 119435 Moscow, Russia
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5
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YB-1 as an Oncoprotein: Functions, Regulation, Post-Translational Modifications, and Targeted Therapy. Cells 2022; 11:cells11071217. [PMID: 35406781 PMCID: PMC8997642 DOI: 10.3390/cells11071217] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/26/2022] [Accepted: 04/02/2022] [Indexed: 02/04/2023] Open
Abstract
Y box binding protein 1 (YB-1) is a protein with a highly conserved cold shock domain (CSD) that also belongs to the family of DNA- and RNA-binding proteins. YB-1 is present in both the nucleus and cytoplasm and plays versatile roles in gene transcription, RNA splicing, DNA damage repair, cell cycle progression, and immunity. Cumulative evidence suggests that YB-1 promotes the progression of multiple tumor types and serves as a potential tumor biomarker and therapeutic target. This review comprehensively summarizes the emerging functions, mechanisms, and regulation of YB-1 in cancers, and further discusses targeted strategies.
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6
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The RNA-Binding Protein YBX3 Controls Amino Acid Levels by Regulating SLC mRNA Abundance. Cell Rep 2019; 27:3097-3106.e5. [DOI: 10.1016/j.celrep.2019.05.039] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/29/2019] [Accepted: 05/10/2019] [Indexed: 01/23/2023] Open
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7
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Li Z, Yang F, Xuan Y, Xi R, Zhao R. Pelota-interacting G protein Hbs1 is required for spermatogenesis in Drosophila. Sci Rep 2019; 9:3226. [PMID: 30824860 PMCID: PMC6397311 DOI: 10.1038/s41598-019-39530-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 01/08/2019] [Indexed: 12/31/2022] Open
Abstract
Hbs1, which is homologous to the GTPase eRF3, is a small G protein implicated in mRNA quality control. It interacts with a translation-release factor 1-like protein Dom34/Pelota to direct decay of mRNAs with ribosomal stalls. Although both proteins are evolutionarily conserved in eukaryotes, the biological function of Hbs1 in multicellular organisms is yet to be characterized. In Drosophila, pelota is essential for the progression through meiosis during spermatogenesis and germline stem cell maintenance. Here we show that homozygous Hbs1 mutant flies are viable, female-fertile, but male-sterile, which is due to defects in meiosis and spermatid individualization, phenotypes that are also observed in pelota hypomorphic mutants. In contrast, Hbs1 mutants have no obvious defects in germline stem cell maintenance. We show that Hbs1 genetically interacts with pelota during spermatid individualization. Furthermore, Pelota with a point mutation on the putative Hbs1-binding site cannot substitute the wild type protein for normal spermatogenesis. These data suggest that Pelota forms a complex with Hbs1 to regulate multiple processes during spermatogenesis. Our results reveal a specific requirement of Hbs1 in male gametogenesis in Drosophila and indicate an essential role for the RNA surveillance complex Pelota-Hbs1 in spermatogenesis, a function that could be conserved in mammals.
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Affiliation(s)
- Zhaohui Li
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.,National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Fu Yang
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Yang Xuan
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Rongwen Xi
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
| | - Rui Zhao
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China. .,Genomics Institute of the Novartis Research Foundation, San Diego, California, 92121, USA.
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8
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Issigonis M, Newmark PA. From worm to germ: Germ cell development and regeneration in planarians. Curr Top Dev Biol 2019; 135:127-153. [DOI: 10.1016/bs.ctdb.2019.04.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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9
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Wu Y, Xu K, Qi H. Domain-functional analyses of PIWIL1 and PABPC1 indicate their synergistic roles in protein translation via 3′-UTRs of meiotic mRNAs†. Biol Reprod 2018; 99:773-788. [DOI: 10.1093/biolre/ioy100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 04/24/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
- Yaoyao Wu
- School of Life Science, University of Science and Technology of China, Hefei, China
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Kaibiao Xu
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Huayu Qi
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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10
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NF-YB Regulates Spermatogonial Stem Cell Self-Renewal and Proliferation in the Planarian Schmidtea mediterranea. PLoS Genet 2016; 12:e1006109. [PMID: 27304889 PMCID: PMC4909293 DOI: 10.1371/journal.pgen.1006109] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 05/16/2016] [Indexed: 12/21/2022] Open
Abstract
Gametes are the source and carrier of genetic information, essential for the propagation of all sexually reproducing organisms. Male gametes are derived from a progenitor stem cell population called spermatogonial stem cells (SSCs). SSCs give rise to male gametes through the coordination of two essential processes: self-renewal to produce more SSCs, and differentiation to produce mature sperm. Disruption of this equilibrium can lead to excessive proliferation of SSCs, causing tumorigenesis, or can result in aberrant differentiation, leading to infertility. Little is known about how SSCs achieve the fine balance between self-renewal and differentiation, which is necessary for their remarkable output and developmental potential. To understand the mechanisms of SSC maintenance, we examine the planarian homolog of Nuclear Factor Y-B (NF-YB), which is required for the maintenance of early planarian male germ cells. Here, we demonstrate that NF-YB plays a role in the self-renewal and proliferation of planarian SSCs, but not in their specification or differentiation. Furthermore, we characterize members of the NF-Y complex in Schistosoma mansoni, a parasitic flatworm related to the free-living planarian. We find that the function of NF-YB in regulating male germ cell proliferation is conserved in schistosomes. This finding is especially significant because fecundity is the cause of pathogenesis of S. mansoni. Our findings can help elucidate the complex relationship between self-renewal and differentiation of SSCs, and may also have implications for understanding and controlling schistosomiasis.
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11
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Takeda N, Yoshinaga K, Furushima K, Takamune K, Li Z, Abe SI, Aizawa SI, Yamamura KI. Viable offspring obtained from Prm1-deficient sperm in mice. Sci Rep 2016; 6:27409. [PMID: 27250771 PMCID: PMC4890041 DOI: 10.1038/srep27409] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/18/2016] [Indexed: 12/14/2022] Open
Abstract
Protamines are expressed in the spermatid nucleus and allow denser packaging of DNA compared with histones. Disruption of the coding sequence of one allele of either protamine 1 (Prm1) or Prm2 results in failure to produce offspring, although sperm with disrupted Prm1 or Prm2 alleles are produced. Here, we produced Prm1-deficient female chimeric mice carrying Prm1-deficient oocytes. These mice successfully produced Prm1(+/-) male mice. Healthy Prm1(+/-) offspring were then produced by transferring blastocysts obtained via in vitro fertilization using zona-free oocytes and sperm from Prm1(+/-) mice. This result suggests that sperm lacking Prm1 can generate offspring despite being abnormally shaped and having destabilised DNA, decondensed chromatin and a reduction in mitochondrial membrane potential. Nevertheless, these mice showed little derangement of expression profiles.
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Affiliation(s)
- Naoki Takeda
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan
| | - Kazuya Yoshinaga
- Department of Anatomy, Graduate School of Health Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0975, Japan
| | - Kenryo Furushima
- Department of Molecular Cell Biology and Molecular Medicine, Institute of Advanced Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan
| | - Kazufumi Takamune
- Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
| | - Zhenghua Li
- Department of Histology and Embryology, Harbin Medical University, Harbin 150081, China
| | - Shin-Ichi Abe
- Kumamoto Health Science University, 325 Izumi-machi, Kita-ku, Kumamoto 861-5598, Japan
| | - Shin-Ichi Aizawa
- Center for Developmental Biology, RIKEN Kobe, 2-2-3 Minatojima Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Ken-Ichi Yamamura
- Yamamura Project Laboratory, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
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12
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Kleene KC. Position-dependent interactions of Y-box protein 2 (YBX2) with mRNA enable mRNA storage in round spermatids by repressing mRNA translation and blocking translation-dependent mRNA decay. Mol Reprod Dev 2016; 83:190-207. [PMID: 26773323 DOI: 10.1002/mrd.22616] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/08/2016] [Indexed: 12/18/2022]
Abstract
Many mRNAs encoding proteins needed for the construction of the specialized organelles of spermatozoa are stored as translationally repressed, free messenger ribonucleoproteins in round spermatids, to be actively translated in elongating and elongated spermatids. The factors that repress translation in round spermatids, however, have been elusive. Two lines of evidence implicate the highly abundant and well-known translational repressor, Y-box protein 2 (YBX2), as a critical factor: First, protamine 1 (Prm1) and sperm-mitochondria cysteine-rich protein (Smcp) mRNAs are prematurely recruited onto polysomes in Ybx2-knockout mouse round spermatids. Second, mutations in 3' untranslated region (3'UTR) cis-elements that abrogate YBX2 binding activate translation of Prm1 and Smcp mRNAs in round spermatids of transgenic mice. The abundance of YBX2 and its affinity for variable sequences, however, raise questions of how YBX2 targets specific mRNAs for repression. Mutations to the Prm1 and Smcp mRNAs in transgenic mice reveal that strong repression in round spermatids requires YBX2 binding sites located near the 3' ends of their 3'UTRs as locating the same sites in upstream positions produce negligible repression. This location-dependence implies that the assembly of repressive complexes is nucleated by adjacent cis-elements that enable cooperative interactions of YBX2 with co-factors. The available data suggest that, in vertebrates, YBX2 has the important role of coordinating the storage of translationally repressed mRNAs in round spermatids by inhibiting translational activity and the degradation of transcripts via translation-dependent deadenylation. These insights should facilitiate future experiments designed to unravel how YBX2 targets mRNAs for repression in round spermatids and how mutations in the YBX2 gene cause infertility in humans. Mol. Reprod. Dev. 83: 190-207, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kenneth C Kleene
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts
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13
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Licatalosi DD. Roles of RNA-binding Proteins and Post-transcriptional Regulation in Driving Male Germ Cell Development in the Mouse. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:123-51. [PMID: 27256385 DOI: 10.1007/978-3-319-29073-7_6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tissue development and homeostasis are dependent on highly regulated gene expression programs in which cell-specific combinations of regulatory factors determine which genes are expressed and the post-transcriptional fate of the resulting RNA transcripts. Post-transcriptional regulation of gene expression by RNA-binding proteins has critical roles in tissue development-allowing individual genes to generate multiple RNA and protein products, and the timing, location, and abundance of protein synthesis to be finely controlled. Extensive post-transcriptional regulation occurs during mammalian gametogenesis, including high levels of alternative mRNA expression, stage-specific expression of mRNA variants, broad translational repression, and stage-specific activation of mRNA translation. In this chapter, an overview of the roles of RNA-binding proteins and the importance of post-transcriptional regulation in male germ cell development in the mouse is presented.
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Affiliation(s)
- Donny D Licatalosi
- Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH, 44106, USA.
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14
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Snyder E, Soundararajan R, Sharma M, Dearth A, Smith B, Braun RE. Compound Heterozygosity for Y Box Proteins Causes Sterility Due to Loss of Translational Repression. PLoS Genet 2015; 11:e1005690. [PMID: 26646932 PMCID: PMC4672889 DOI: 10.1371/journal.pgen.1005690] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 10/30/2015] [Indexed: 11/18/2022] Open
Abstract
The Y-box proteins YBX2 and YBX3 bind RNA and DNA and are required for metazoan development and fertility. However, possible functional redundancy between YBX2 and YBX3 has prevented elucidation of their molecular function as RNA masking proteins and identification of their target RNAs. To investigate possible functional redundancy between YBX2 and YBX3, we attempted to construct Ybx2-/-;Ybx3-/- double mutants using a previously reported Ybx2-/- model and a newly generated global Ybx3-/- model. Loss of YBX3 resulted in reduced male fertility and defects in spermatid differentiation. However, homozygous double mutants could not be generated as haploinsufficiency of both Ybx2 and Ybx3 caused sterility characterized by extensive defects in spermatid differentiation. RNA sequence analysis of mRNP and polysome occupancy in single and compound Ybx2/3 heterozygotes revealed loss of translational repression almost exclusively in the compound Ybx2/3 heterozygotes. RNAseq analysis also demonstrated that Y-box protein dose-dependent loss of translational regulation was inversely correlated with the presence of a Y box recognition target sequence, suggesting that Y box proteins bind RNA hierarchically to modulate translation in a range of targets. The Y-box proteins are evolutionary conserved across eukaryotes. This study focused on two Y-box proteins, YBX2 and YBX3, expressed in testis and known be important for male fertility. Previous studies in male germ cells link YBX2 and YBX3 proteins to RNA masking, however, whether they function in translational repression or mRNA stability during spermatogenesis has not been resolved. Ybx2-null mice are known to be infertile due to post-meiotic spermatid defects. To assess the functional role of YBX3 during spermatogenesis, we generated Ybx3-null mice. These mice displayed reduced fertility and spermatid differentiation defects. To test if YBX2 and YBX3 are functionally redundant, we attempted to generate double knockout mice. Double mutants could not be generated due to unexpected infertility in the compound Ybx2/3 heterozygotes. Compound heterozygotes displayed multiple sperm defects indicative of failed post-meiotic germ cell differentiation. Analysis of translational repression in compound Ybx2/3 heterozygous testes demonstrated a loss of translation repression in mRNAs lacking the Y box recognition sequence. These findings suggest YBX2 and YBX3 function to repress translation through both sequence-specific and non-specific mechanisms in a hierarchical manner.
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Affiliation(s)
- Elizabeth Snyder
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Manju Sharma
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Andrea Dearth
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Benjamin Smith
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Robert E. Braun
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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Cullinane DL, Chowdhury TA, Kleene KC. Mechanisms of translational repression of the Smcp mRNA in round spermatids. Reproduction 2014; 149:43-54. [PMID: 25336347 DOI: 10.1530/rep-14-0394] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The protamine 1 (Prm1) and sperm mitochondria-associated, cysteine-rich protein (Smcp) mRNAs exemplify a widespread pattern of mRNA-specific regulation of mRNA translation in post-meiotic spermatogenic cells, spermatids. Both mRNAs are transcribed and initially stored in free-mRNPs in early spermatids, and translated on polysomes in late spermatids. In this study, we demonstrate that the 5' and 3'-UTRs and the 3' terminus of the Smcp 3'-UTR are required for normal repression of the Smcp mRNA in transgenic mice. RNA affinity chromatography and mass spectrometry sequencing identified Y-box protein 2 (YBX2/MSY2) as the major protein that interacts with the 3' terminus of the Smcp 3'-UTR and a Y-box recognition sequence, GCCACCU, in the translation control element that is necessary for Prm1 mRNA repression. Depletion of YBX2 in Ybx2-null mice prematurely activates Prm1 and Smcp mRNA translation in early spermatids. Fluorescent in situ hybridization reveals that the Smcp intron, the Smcp mRNA, and both Smcp-Gfp transgenic mRNAs are strongly concentrated in the chromatoid body, and that theYbx2-null mutation does not eliminate the Smcp mRNA from the chromatoid body. This and previous findings suggest that the Smcp pre-mRNA is spliced and associates with YBX2 in the chromatoid body, and that repressed free-mRNPs are stored in the general cytoplasm. As YBX2 is the predominant protein in testis free-mRNPs, it likely represses many mRNAs in early spermatids. The mechanisms by which YBX2 represses the Smcp and Prm1 mRNAs are relevant to reproductive medicine because mutations in the human YBX2 gene correlate with abnormal protamine expression and male infertility.
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Affiliation(s)
- Danielle L Cullinane
- Department of BiologyUniversity of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125-3393, USA
| | - Tamjid A Chowdhury
- Department of BiologyUniversity of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125-3393, USA
| | - Kenneth C Kleene
- Department of BiologyUniversity of Massachusetts Boston, 100 Morrissey Boulevard, Boston, Massachusetts 02125-3393, USA
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Xu K, Yang L, Zhao D, Wu Y, Qi H. AKAP3 synthesis is mediated by RNA binding proteins and PKA signaling during mouse spermiogenesis. Biol Reprod 2014; 90:119. [PMID: 24648398 DOI: 10.1095/biolreprod.113.116111] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian spermatogenesis is regulated by coordinated gene expression in a spatiotemporal manner. The spatiotemporal regulation of major sperm proteins plays important roles during normal development of the male gamete, of which the underlying molecular mechanisms are poorly understood. A-kinase anchoring protein 3 (AKAP3) is one of the major components of the fibrous sheath of the sperm tail that is formed during spermiogenesis. In the present study, we analyzed the expression of sperm-specific Akap3 and the potential regulatory factors of its protein synthesis during mouse spermiogenesis. Results showed that the transcription of Akap3 precedes its protein synthesis by about 2 wk. Nascent AKAP3 was found to form protein complex with PKA and RNA binding proteins (RBPs), including PIWIL1, PABPC1, and NONO, as revealed by coimmunoprecipitation and protein mass spectrometry. RNA electrophoretic gel mobility shift assay showed that these RBPs bind sperm-specific mRNAs, of which proteins are synthesized during the elongating stage of spermiogenesis. Biochemical and cell biological experiments demonstrated that PIWIL1, PABPC1, and NONO interact with each other and colocalize in spermatids' RNA granule, the chromatoid body. In addition, NONO was found in extracytoplasmic granules in round spermatids, whereas PIWIL1 and PABPC1 were diffusely localized in cytoplasm of elongating spermatids, indicating their participation at different steps of mRNA metabolism during spermatogenesis. Interestingly, type I PKA subunits colocalize with PIWIL1 and PABPC1 in the cytoplasm of elongating spermatids and cosediment with the RBPs in polysomal fractions on sucrose gradients. Further biochemical analyses revealed that activation of PKA positively regulates AKAP3 protein synthesis without changing its mRNA level in elongating spermatids. Taken together, these results indicate that PKA signaling directly participates in the regulation of protein translation in postmeiotic male germ cells, underscoring molecular mechanisms that regulate protein synthesis during mouse spermiogenesis.
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Affiliation(s)
- Kaibiao Xu
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Lele Yang
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Danyun Zhao
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yaoyao Wu
- Department of Biology, University of Science and Technology of China, Hefei, China
| | - Huayu Qi
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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Kleene KC. Connecting cis-elements and trans-factors with mechanisms of developmental regulation of mRNA translation in meiotic and haploid mammalian spermatogenic cells. Reproduction 2013; 146:R1-19. [DOI: 10.1530/rep-12-0362] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
mRNA-specific regulation of translational activity plays major roles in directing the development of meiotic and haploid spermatogenic cells in mammals. Although many RNA-binding proteins (RBPs) have been implicated in normal translational control and sperm development, little is known about the keystone of the mechanisms: the interactions of RBPs and microRNAs withcis-elements in mRNA targets. The problems in connecting factors and elements with translational control originate in the enormous complexity of post-transcriptional regulation in mammalian cells. This creates confusion as to whether factors have direct or indirect and large or small effects on the translation of specific mRNAs. This review argues that gene knockouts, heterologous systems, and overexpression of factors cannot provide convincing answers to these questions. As a result, the mechanisms involving well-studied mRNAs (Ddx4/Mvh,Prm1,Prm2, andSycp3) and factors (DICER1, CPEB1, DAZL, DDX4/MVH, DDX25/GRTH, translin, and ELAV1/HuR) are incompletely understood. By comparison, mutations in elements can be used to define the importance of specific pathways in regulating individual mRNAs. However, few elements have been studied, because the only reliable system to analyze mutations in elements, transgenic mice, is considered impractical. This review describes advances that may facilitate identification of the direct targets of RBPs and analysis of mutations incis-elements. The importance of upstream reading frames in the developmental regulation of mRNA translation in spermatogenic cells is also documented.
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Vourekas A, Zheng Q, Alexiou P, Maragkakis M, Kirino Y, Gregory BD, Mourelatos Z. Mili and Miwi target RNA repertoire reveals piRNA biogenesis and function of Miwi in spermiogenesis. Nat Struct Mol Biol 2012; 19:773-81. [PMID: 22842725 PMCID: PMC3414646 DOI: 10.1038/nsmb.2347] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 06/25/2012] [Indexed: 01/31/2023]
Abstract
Germ cells implement elaborate mechanisms to protect their genetic material and to regulate gene expression during differentiation. Piwi proteins bind piRNAs, a class of small germline RNAs whose biogenesis and functions are still largely elusive. We employed high throughput sequencing after crosslinking and immunoprecipitation (HITS-CLIP) coupled with RNA-Seq to characterize the genome-wide target RNA repertoire of Mili (Piwil2) and Miwi (Piwil1), two Piwi proteins expressed in mouse postnatal testis. We report the in vivo pathway of primary piRNA biogenesis and implicate distinct nucleolytic activities that process Piwi-bound precursor transcripts. Our studies indicate that pachytene piRNAs are the end products of RNA processing. HITS-CLIP demonstrates that Miwi binds spermiogenic mRNAs directly, without utilizing piRNAs as guides, and independent biochemical analyses of testis mRNA-ribonucleoproteins (mRNPs) establishes that Miwi functions in the formation of mRNP complexes that stabilize mRNAs essential for spermiogenesis.
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Affiliation(s)
- Anastassios Vourekas
- Department of Pathology and Laboratory Medicine, Division of Neuropathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Hou Y, Yuan J, Zhou X, Fu X, Cheng H, Zhou R. DNA demethylation and USF regulate the meiosis-specific expression of the mouse Miwi. PLoS Genet 2012; 8:e1002716. [PMID: 22661915 PMCID: PMC3355075 DOI: 10.1371/journal.pgen.1002716] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/30/2012] [Indexed: 01/01/2023] Open
Abstract
Miwi, a member of the Argonaute family, is required for initiating spermiogenesis; however, the mechanisms that regulate the expression of the Miwi gene remain unknown. By mutation analysis and transgenic models, we identified a 303 bp proximal promoter region of the mouse Miwi gene, which controls specific expression from midpachytene spermatocytes to round spermatids during meiosis. We characterized the binding sites of transcription factors NF-Y (Nuclear Factor Y) and USF (Upstream Stimulatory Factor) within the core promoter and found that both factors specifically bind to and activate the Miwi promoter. Methylation profiling of three CpG islands within the proximal promoter reveals a markedly inverse correlation between the methylation status of the CpG islands and germ cell type–specific expression of Miwi. CpG methylation at the USF–binding site within the E2 box in the promoter inhibits the binding of USF. Transgenic Miwi-EGFP and endogenous Miwi reveal a subcellular co-localization pattern in the germ cells of the Miwi-EGFP transgenic mouse. Furthermore, the DNA methylation profile of the Miwi promoter–driven transgene is consistent with that of the endogenous Miwi promoter, indicating that Miwi transgene is epigenetically modified through methylation in vivo to ensure its spatio-temporal expression. Our findings suggest that USF controls Miwi expression from midpachytene spermatocytes to round spermatids through methylation-mediated regulation. This work identifies an epigenetic regulation mechanism for the spatio-temporal expression of mouse Miwi during spermatogenesis. Germ cell differentiation is a key process in the formation of functional spermatozoa. Despite the wealth of information about gene expression patterns and regulations important for this process, it is not clear how spatio-temporal expression of the key factor Miwi during spermatogenesis is controlled. We have characterized the functional promoter of the mouse Miwi gene. Transgenic mice harboring EGFP under the Miwi core promoter containing just the functional CCAAT box and E2 box were generated and demonstrated that it can direct germ cell–specific expression. We further identified the transcription factors NF-Y and USF1/2 as activators of Miwi gene expression, through their binding to the CCAAT box and E-box/E2 site of the Miwi promoter, respectively. A CpG dinucleotide just located within the USF binding site is responsible for mediating methylation-dependent silencing of the Miwi gene. Our findings provide new insight into an epigenetic regulation mechanism for the spatio-temporal expression of the mouse Miwi during spermatogenesis.
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Affiliation(s)
| | | | | | | | - Hanhua Cheng
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (HC); (RZ)
| | - Rongjia Zhou
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (HC); (RZ)
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Chauvin TR, Herndon MK, Nilson JH. Cold-shock-domain protein A (CSDA) contributes posttranscriptionally to gonadotropin-releasing hormone-regulated expression of Egr1 and indirectly to Lhb. Biol Reprod 2012; 86:53. [PMID: 22053098 DOI: 10.1095/biolreprod.111.093658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Gonadotropin-releasing hormone (GnRH), a hypothalamic neurohormone, regulates transcription of Lhb in gonadotrophs indirectly through transient induction and accumulation of EGR1, a zinc finger transcription factor. AlphaT3 and LbetaT2 cell lines model gonadotrophs at two distinct stages of development, prenatal and postnatal expression of Lhb. Although GnRH induces EGR1 in both cell lines, the levels of the DNA-binding protein are lower and disappear more quickly in alphaT3 than in LbetaT2 cells. Herein we show that overexpression of Egr1 in alphaT3 cells rescues activity of a transfected LHB promoter-reporter, suggesting that its transcription is dependent on EGR1 crossing a critical concentration threshold. We also show that Csda, a gene that encodes an RNA-binding protein and is a member of the cold-shock-domain (CSD) family, is expressed at higher levels in LbetaT2 compared to alphaT3 cells. Transient expression studies indicate that at least one Csd element, residing in the 3' untranslated region of Egr1 mRNA, increases activity of a chimeric pGL3 luciferase reporter vector in LbetaT2 cells. Additional experiments indicate that CSDA physically interacts with Egr1 mRNA. Furthermore, siRNA-mediated reduction of endogenous Csda mRNA attenuates GnRH regulation of a transiently transfected LHB reporter vector. Taken together, these studies suggest that CSDA contributes posttranscriptionally to GnRH-regulated expression of Egr1, thereby enabling the transcription factor to cross a critical concentration threshold necessary for maximal accumulation of Lhb mRNA in response to the neurohormone.
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Affiliation(s)
- Theodore R Chauvin
- School of Molecular Biosciences, Washington State University, Pullman, 99164-7520, USA
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21
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Chong T, Stary JM, Wang Y, Newmark PA. Molecular markers to characterize the hermaphroditic reproductive system of the planarian Schmidtea mediterranea. BMC DEVELOPMENTAL BIOLOGY 2011; 11:69. [PMID: 22074376 PMCID: PMC3224759 DOI: 10.1186/1471-213x-11-69] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 11/10/2011] [Indexed: 12/05/2022]
Abstract
Background The freshwater planarian Schmidtea mediterranea exhibits two distinct reproductive modes. Individuals of the sexual strain are cross-fertilizing hermaphrodites with reproductive organs that develop post-embryonically. By contrast, individuals of the asexual strain reproduce exclusively by transverse fission and fail to develop reproductive organs. These different reproductive strains are associated with distinct karyotypes, making S. mediterranea a useful model for studying germline development and sexual differentiation. Results To identify genes expressed differentially between these strains, we performed microarray analyses and identified >800 genes that were upregulated in the sexual planarian. From these, we characterized 24 genes by fluorescent in situ hybridization (FISH), revealing their expression in male germ cells or accessory reproductive organs. To identify additional markers of the planarian reproductive system, we also used immuno- and fluorescent lectin staining, identifying several antibodies and lectins that labeled structures associated with reproductive organs. Conclusions Collectively, these cell-type specific markers will enable future efforts to characterize genes that are important for reproductive development in the planarian.
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Affiliation(s)
- Tracy Chong
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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22
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Kleene KC, Cullinane DL. Maybe repressed mRNAs are not stored in the chromatoid body in mammalian spermatids. Reproduction 2011; 142:383-8. [DOI: 10.1530/rep-11-0113] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The chromatoid body is a dynamic organelle that is thought to coordinate the cytoplasmic regulation of mRNA translation and degradation in mammalian spermatids. The chromatoid body is also postulated to function in repression of mRNA translation by sequestering dormant mRNAs where they are inaccessible to the translational apparatus. This review finds no convincing evidence that dormant mRNAs are localized exclusively in the chromatoid body. This discrepancy can be explained by two hypotheses. First, experimental artifacts, possibly related to peculiarities of the structure and function of the chromatoid body, preclude obtaining an accurate indication of mRNA localization. Second, mRNA is not stored in the chromatoid body, because, like perinuclear P granules in Caenorhabditis elegans, the chromatoid body functions as a center for mRNP remodeling and export to other cytoplasmic sites.
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Wang Y, Stary JM, Wilhelm JE, Newmark PA. A functional genomic screen in planarians identifies novel regulators of germ cell development. Genes Dev 2010; 24:2081-92. [PMID: 20844018 DOI: 10.1101/gad.1951010] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms.
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Affiliation(s)
- Yuying Wang
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Kini HK, Vishnu MR, Liebhaber SA. Too much PABP, too little translation. J Clin Invest 2010; 120:3090-3. [PMID: 20739750 DOI: 10.1172/jci44091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional regulation is of critical importance during mammalian spermiogenesis. A set of mRNAs that encode proteins critical to normal sperm formation are synthesized early in the process of male germ cell differentiation and are stored in a repressed state. These mRNAs are subsequently translationally activated during the process of spermatid elongation and maturation. Of note, the translationally repressed mRNAs contain long poly(A) tails that are dramatically shortened during the translational activation process. Understanding the mechanisms that underlie this process of mRNA storage and subsequent translational activation has been a long-standing goal. The relationship of the poly(A) tail to translational control is intimately related to the functions of the cognate poly(A)-binding proteins (PABPs). In this issue of the JCI, Yanagiya and colleagues use a set of knockout mice to demonstrate a novel functional role for a particular modulator of PABP function, PABP-interacting protein 2a (PAIP2A), in the normal terminal differentiation of male germ cells.
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Affiliation(s)
- Hemant K Kini
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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25
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Hermo L, Pelletier RM, Cyr DG, Smith CE. Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 4: intercellular bridges, mitochondria, nuclear envelope, apoptosis, ubiquitination, membrane/voltage-gated channels, methylation/acetylation, and transcription factors. Microsc Res Tech 2010; 73:364-408. [PMID: 19941288 DOI: 10.1002/jemt.20785] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
As germ cells divide and differentiate from spermatogonia to spermatozoa, they share a number of structural and functional features that are common to all generations of germ cells and these features are discussed herein. Germ cells are linked to one another by large intercellular bridges which serve to move molecules and even large organelles from the cytoplasm of one cell to another. Mitochondria take on different shapes and features and topographical arrangements to accommodate their specific needs during spermatogenesis. The nuclear envelope and pore complex also undergo extensive modifications concomitant with the development of germ cell generations. Apoptosis is an event that is normally triggered by germ cells and involves many proteins. It occurs to limit the germ cell pool and acts as a quality control mechanism. The ubiquitin pathway comprises enzymes that ubiquitinate as well as deubiquitinate target proteins and this pathway is present and functional in germ cells. Germ cells express many proteins involved in water balance and pH control as well as voltage-gated ion channel movement. In the nucleus, proteins undergo epigenetic modifications which include methylation, acetylation, and phosphorylation, with each of these modifications signaling changes in chromatin structure. Germ cells contain specialized transcription complexes that coordinate the differentiation program of spermatogenesis, and there are many male germ cell-specific differences in the components of this machinery. All of the above features of germ cells will be discussed along with the specific proteins/genes and abnormalities to fertility related to each topic.
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Affiliation(s)
- Louis Hermo
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, 3640 University Street, Montreal, QC Canada H3A 2B2.
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Suzuki H, Saba R, Sada A, Saga Y. The Nanos3-3'UTR is required for germ cell specific NANOS3 expression in mouse embryos. PLoS One 2010; 5:e9300. [PMID: 20174582 PMCID: PMC2823788 DOI: 10.1371/journal.pone.0009300] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2009] [Accepted: 01/25/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The regulation of gene expression via a 3' untranslated region (UTR) plays essential roles in the discrimination of the germ cell lineage from somatic cells during embryogenesis. This is fundamental to the continuation of a species. Mouse NANOS3 is an essential protein required for the germ cell maintenance and is specifically expressed in these cells. However, the regulatory mechanisms that restrict the expression of this gene in the germ cells is largely unknown at present. METHODOLOGY/PRINCIPAL FINDINGS In our current study, we show that differences in the stability of Nanos3 mRNA between germ cells and somatic cells is brought about in a 3'UTR-dependent manner in mouse embryos. Although Nanos3 is transcribed in both cell lineages, it is efficiently translated only in the germ lineage. We also find that the translational suppression of NANOS3 in somatic cells is caused by a 3'UTR-mediated mRNA destabilizing mechanism. Surprisingly, even when under the control of the CAG promoter which induces strong ubiquitous transcription in both germ cells and somatic cells, the addition of the Nanos3-3'UTR sequence to the coding region of exogenous gene was effective in restricting protein expression in germ cells. CONCLUSIONS/SIGNIFICANCE Our current study thus suggests that Nanos3-3'UTR has an essential role in translational control in the mouse embryo.
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Affiliation(s)
- Hitomi Suzuki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Rie Saba
- Division of Mammalian Development, National Institute of Genetics, Shizuoka, Japan
| | - Aiko Sada
- Department of Genetics, The Graduate University for Advanced Studies (Sokendai), Shizuoka, Japan
| | - Yumiko Saga
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
- Division of Mammalian Development, National Institute of Genetics, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies (Sokendai), Shizuoka, Japan
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Liu Z, Zhou S, Liao L, Chen X, Meistrich M, Xu J. Jmjd1a demethylase-regulated histone modification is essential for cAMP-response element modulator-regulated gene expression and spermatogenesis. J Biol Chem 2009; 285:2758-70. [PMID: 19910458 DOI: 10.1074/jbc.m109.066845] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Spermatogenesis, a fundamental process in the male reproductive system, requires a series of tightly controlled epigenetic and genetic events in germ cells ranging from spermatogonia to spermatozoa. Jmjd1a is a key epigenetic regulator expressed in the testis. It specifically demethylates mono- and di-methylated histone H3 lysine 9 (H3K9me1 and H3K9me2) but not tri-methylated H3K9 (H3K9me3). In this study, we generated a Jmjd1a antibody for immunohistochemistry and found Jmjd1a was specifically produced in pachytene and secondary spermatocytes. Disruption of the Jmjd1a gene in mice significantly increased H3K9me1 and H3K9me2 levels in pachytene spermatocytes and early elongating spermatids without affecting H3K9me3 levels. Concurrently, the levels of histone acetylation were decreased in Jmjd1a knock-out germ cells. This suggests Jmjd1a promotes transcriptional activation by lowering histone methylation and increasing histone acetylation. Interestingly, the altered histone modifications in Jmjd1a-deficient germ cells caused diminished cAMP-response element modulator (Crem) recruitment to chromatin and decreased expression of the Crem coactivator Act and their target genes Tnp1 (transition protein 1), Tnp2, Prm1 (protamine 1), and Prm2, all of which are essential for chromatin condensation in spermatids. In agreement with these findings, Jmjd1a deficiency caused extensive germ cell apoptosis and blocked spermatid elongation, resulting in severe oligozoospermia, small testes, and infertility in male mice. These results indicate that the Jmjd1a-controlled epigenetic histone modifications are crucial for Crem-regulated gene expression and spermatogenesis.
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Affiliation(s)
- Zhaoliang Liu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Texas A&M University Health Science Center, Texas 77030, USA
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Dehari H, Tchaikovskaya T, Rubashevsky E, Sellers R, Listowsky I. The proximal promoter governs germ cell-specific expression of the mouse glutathione transferase mGstm5 gene. Mol Reprod Dev 2009; 76:379-88. [PMID: 18932202 DOI: 10.1002/mrd.20976] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
To explain the tissue-selective expression patterns of a distinct subclass of glutathione S-transferase (GST), transgenic mice expressing EGFP under control of a 2 kb promoter sequence in the 5'-flanking region of the mGstm5 gene were produced. The intent of the study was to establish whether the promoter itself or whether posttranscriptional mechanisms, particularly at the levels of mRNA translation and stability or protein targeting, based on unique properties of mGSTM5, determine the restricted expression pattern. Indeed, the transgene expression was limited to testis as the reporter was not detected in somatic tissues such as brain, kidney or liver, indicating that the mGstm5 proximal promoter is sufficient to target testis-specific expression of the gene. EGFP expression was also more restricted vis-a-vis the natural mGstm5 gene and exclusively found in germ but not in somatic cells. Real-time quantitative PCR (qPCR) data were consistent with alternate transcription start sites in which the promoter region of the natural mGstm5 gene in somatic cells is part of exon 1 of the germ cell transcript. Thus, the primary transcription start site for mGstm5 is upstream of a TATA box in testis and downstream of this motif in somatic cells. The 5' flanking sequence of the mGstm5 gene imparts germ cell-specific transcription.
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Unhavaithaya Y, Hao Y, Beyret E, Yin H, Kuramochi-Miyagawa S, Nakano T, Lin H. MILI, a PIWI-interacting RNA-binding protein, is required for germ line stem cell self-renewal and appears to positively regulate translation. J Biol Chem 2008; 284:6507-19. [PMID: 19114715 DOI: 10.1074/jbc.m809104200] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Argonaute/PIWI protein family consists of Argonaute and PIWI subfamilies. Argonautes function in RNA interference and micro-RNA pathways; whereas PIWIs bind to PIWI-interacting RNAs and regulate germ line development, stem cell maintenance, epigenetic regulation, and transposition. However, the role of PIWIs in mammalian stem cells has not been demonstrated, and molecular mechanisms mediated by PIWIs remain elusive. Here we show that MILI, a murine PIWI protein, is expressed in the cytoplasm of testicular germ line stem cells, spermatogonia, and early spermatocytes, where it is enriched in chromatoid bodies. MILI is essential for the self-renewing division and differentiation of germ line stem cells but does not affect initial establishment of the germ line stem cell population at 7 days postpartum. Furthermore, MILI forms a stable RNA-independent complex with eIF3a and associates with the eIF4E- and eIF4G-containing m7G cap-binding complex. In isolated 7 days postpartum seminiferous tubules containing mostly germ line stem cells, the mili mutation has no effect on the cellular mRNA level yet significantly reduces the rate of protein synthesis. These observations indicate that MILI may positively regulate translation and that such regulation is required for germ line stem cell self-renewal.
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Affiliation(s)
- Yingdee Unhavaithaya
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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31
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Ravel C, Chantot-Bastaraud S, El Houate B, Berthaut I, Verstraete L, De Larouziere V, Lourenço D, Dumaine A, Antoine JM, Mandelbaum J, Siffroi JP, McElreavey K. Mutations in the protamine 1 gene associated with male infertility. ACTA ACUST UNITED AC 2007; 13:461-4. [PMID: 17494104 DOI: 10.1093/molehr/gam031] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In elongating spermatids, human sperm chromatin undergoes a complex compaction in which the transition proteins are extensively replaced by the protamine proteins. Several human studies demonstrate that expression of the protamine proteins is altered in some men with male infertility. For this study, we screened the PRM1 (protamine 1) gene for mutations in a large cohort of 281 men seeking infertility treatment. We identified the c.102G>T transversion that results in an p.Arg34Ser amino acid change in two men. One of these patients presented with oligozoospermia associated with increased sperm DNA fragmentation. The second individual was normospermic but together with his partner sought treatment for idiopathic couple infertility. We also identified a novel missense mutation (c.119G>A, p.Cys40Tyr) in a man with oligoasthenozoospermia. These mutations were not observed in control populations. Interestingly, we also detected variants both 5' and 3' to the PRM1 open-reading frame specifically in infertile individuals. Four individuals with unexplained severe oligozoospermia were heterozygote for a c.-107G>C change that is located at -15 bp from the transcription initiation site of the gene. This mutation may influence PRM1 expression. In addition, a c.*51G>C variant was detected in the 3'UTR of PRM1 specifically in a man with severe oligoasthenozoospermia.
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Affiliation(s)
- C Ravel
- Université Pierre et Marie Curie Paris-6, EA1533, AP-HP, Hôpital Tenon, Paris, France
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32
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Aivatiadou E, Mattei E, Ceriani M, Tilia L, Berruti G. Impaired fertility and spermiogenetic disorders with loss of cell adhesion in male mice expressing an interfering Rap1 mutant. Mol Biol Cell 2007; 18:1530-42. [PMID: 17314400 PMCID: PMC1838989 DOI: 10.1091/mbc.e06-10-0902] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The guanosine trisphosphatase Rap1 serves as a critical player in signal transduction, somatic cell proliferation and differentiation, and cell-cell adhesion by acting through distinct mechanisms. During mouse spermiogenesis, Rap1 is activated and forms a signaling complex with its effector, the serine-threonine kinase B-Raf. To investigate the functional role of Rap1 in male germ cell differentiation, we generated transgenic mice expressing an inactive Rap1 mutant selectively in differentiating spermatids. This expression resulted in a derailment of spermiogenesis due to an anomalous release of immature round spermatids from the seminiferous epithelium within the tubule lumen and in low sperm counts. These spermiogenetic disorders correlated with impaired fertility, with the transgenic males being severely subfertile. Because mutant testis exhibited perturbations in ectoplasmic specializations (ESs), a Sertoli-germ cell-specific adherens junction, we searched for expression of vascular endothelial cadherin (VE-cadherin), an adhesion molecule regulated by Rap1, in spermatogenic cells of wild-type and mutant mice. We found that germ cells express VE-cadherin with a timing strictly related to apical ES formation and function; immature, VE-cadherin-positive spermatids were, however, prematurely released in the transgenic testis. In conclusion, interfering with Rap1 function during spermiogenesis leads to reduced fertility by impairment of germ-Sertoli cell contacts; our transgenic mouse provides an in vivo model to study the regulation of ES dynamics.
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Affiliation(s)
- Evanthia Aivatiadou
- *Laboratory of Cellular and Molecular Biology of Reproduction, Department of Biology, University of Milan, 20133 Milan, Italy
| | - Elisabetta Mattei
- Institute of Neurobiology and Molecular Medicine, Consiglio Nazionale delle Ricerche, 00143 Rome, Italy; and
| | - Michela Ceriani
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy
| | - Leila Tilia
- Institute of Neurobiology and Molecular Medicine, Consiglio Nazionale delle Ricerche, 00143 Rome, Italy; and
| | - Giovanna Berruti
- *Laboratory of Cellular and Molecular Biology of Reproduction, Department of Biology, University of Milan, 20133 Milan, Italy
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33
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Lu ZH, Books JT, Ley TJ. Cold shock domain family members YB-1 and MSY4 share essential functions during murine embryogenesis. Mol Cell Biol 2006; 26:8410-7. [PMID: 16954378 PMCID: PMC1636768 DOI: 10.1128/mcb.01196-06] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three cold shock domain (CSD) family members (YB-1, MSY2, and MSY4) exist in vertebrate species ranging from frogs to humans. YB-1 is expressed throughout embryogenesis and is ubiquitously expressed in adult animals; it protects cells from senescence during periods of proliferative stress. YB-1-deficient embryos die unexpectedly late in embryogenesis (embryonic day 18.5 [E18.5] to postnatal day 1) with a runting phenotype. We have now determined that MSY4, but not MSY2, is also expressed during embryogenesis; its abundance declines substantially from E9.5 to E17.5 and is undetectable on postnatal day 1(adult mice express MSY4 in testes only). Whole-mount analysis revealed similar patterns of YB-1 and MSY4 RNA expression in E11.5 embryos. To determine whether MSY4 delays the death of YB-1-deficient embryos, we created and analyzed MSY4-deficient mice and then generated YB-1 and MSY4 double-knockout embryos. MSY4 is dispensable for normal development and survival, but the testes of adult mice have excessive spermatocyte apoptosis and seminiferous tubule degeneration. Embryos doubly deficient for YB-1 and MSY4 are severely runted and die much earlier (E8.5 to E11.5) than YB-1-deficient embryos, suggesting that MSY4 indeed shares critical cellular functions with YB-1 in the embryonic tissues where they are coexpressed.
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Affiliation(s)
- Zhi Hong Lu
- Division of Oncology, Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110-1093, USA
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34
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Juliano CE, Voronina E, Stack C, Aldrich M, Cameron AR, Wessel GM. Germ line determinants are not localized early in sea urchin development, but do accumulate in the small micromere lineage. Dev Biol 2006; 300:406-15. [PMID: 16970939 DOI: 10.1016/j.ydbio.2006.07.035] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 07/20/2006] [Accepted: 07/27/2006] [Indexed: 11/26/2022]
Abstract
Two distinct modes of germ line determination are used throughout the animal kingdom: conditional-an inductive mechanism, and autonomous-an inheritance of maternal factors in early development. This study identifies homologs of germ line determinants in the sea urchin Strongylocentrotus purpuratus to examine its mechanism of germ line determination. A list of conserved germ-line associated genes from diverse organisms was assembled to search the S. purpuratus genome for homologs, and the expression patterns of these genes were examined during embryogenesis by whole mount in situ RNA hybridization and QPCR. Of the 14 genes tested, all transcripts accumulate uniformly during oogenesis and Sp-pumilio, Sp-tudor, Sp-MSY, and Sp-CPEB1 transcripts are also uniformly distributed during embryonic development. Sp-nanos2, Sp-seawi, and Sp-ovo transcripts, however, are enriched in the vegetal plate of the mesenchyme blastula stage and Sp-vasa, Sp-nanos2, Sp-seawi, and Sp-SoxE transcripts are localized in small micromere descendents at the tip of the archenteron during gastrulation and are then enriched in the left coelomic pouch of larvae. The results of this screen suggest that sea urchins conditionally specify their germ line, and support the hypothesis that this mechanism is the basal mode of germ line determination amongst deuterostomes. Furthermore, accumulation of germ line determinants selectively in small micromere descendents supports the hypothesis that these cells contribute to the germ line.
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Affiliation(s)
- Celina E Juliano
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 69 Brown Street, Providence, RI 02912, USA
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35
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Skabkin MA, Lyabin DN, Ovchinnikov LP. Nonspecific and specific interactions of Y-box-binding protein 1 (YB-1) with mRNA and posttranscriptional regulation of protein synthesis in animal cells. Mol Biol 2006. [DOI: 10.1134/s0026893306040078] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Ciolofan C, Li XB, Olson C, Kamasawa N, Gebhardt BR, Yasumura T, Morita M, Rash JE, Nagy JI. Association of connexin36 and zonula occludens-1 with zonula occludens-2 and the transcription factor zonula occludens-1-associated nucleic acid-binding protein at neuronal gap junctions in rodent retina. Neuroscience 2006; 140:433-51. [PMID: 16650609 PMCID: PMC1819557 DOI: 10.1016/j.neuroscience.2006.02.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 01/21/2006] [Accepted: 02/08/2006] [Indexed: 11/16/2022]
Abstract
Most gap junctions between neurons in mammalian retina contain abundant connexin36, often in association with the scaffolding protein zonula occludens-1. We now investigate co-association of connexin36, zonula occludens-1, zonula occludens-2 and Y-box transcription factor 3 (zonula occludens-1-associated nucleic acid-binding protein) in mouse and rat retina. By immunoblotting, zonula occludens-1-associated nucleic acid-binding protein and zonula occludens-2 were both detected in retina, and zonula occludens-2 in retina was found to co-immunoprecipitate with connexin36. By immunofluorescence, the four proteins appeared as puncta distributed in the plexiform layers. In the inner plexiform layer, most connexin36-puncta were co-localized with zonula occludens-1, and many were co-localized with zonula occludens-1-associated nucleic acid-binding protein. Moreover, zonula occludens-1-associated nucleic acid-binding protein was often co-localized with zonula occludens-1. Nearly all zonula occludens-2-puncta were positive for connexin36, zonula occludens-1 and zonula occludens-1-associated nucleic acid-binding protein. In the outer plexiform layer, connexin36 was also often co-localized with zonula occludens-1-associated nucleic acid-binding protein. In connexin36 knockout mice, labeling of zonula occludens-1 was slightly reduced in the inner plexiform layer, zonula occludens-1-associated nucleic acid-binding protein was decreased in the outer plexiform layer, and both zonula occludens-1-associated nucleic acid-binding protein and zonula occludens-2 were markedly decreased in the inner sublamina of the inner plexiform layer, whereas zonula occludens-1, zonula occludens-2 and zonula occludens-1-associated nucleic acid-binding protein puncta persisted and remained co-localized in the outer sublamina of the inner plexiform layer. By freeze-fracture replica immunogold labeling, connexin36 was found to be co-localized with zonula occludens-2 within individual neuronal gap junctions. In addition, zonula occludens-1-associated nucleic acid-binding protein was abundant in a portion of ultrastructurally-defined gap junctions throughout the inner plexiform layer, and some of these junctions contained both connexin36 and zonula occludens-1-associated nucleic acid-binding protein. These distinct patterns of connexin36 association with zonula occludens-1, zonula occludens-2 and zonula occludens-1-associated nucleic acid-binding protein in different sublaminae of retina, and differential responses of these proteins to connexin36 gene deletion suggest differential regulatory and scaffolding roles of these gap junction accessory proteins. Further, the persistence of a subpopulation of zonula occludens-1/zonula occludens-2/zonula occludens-1-associated nucleic acid-binding protein co-localized puncta in the outer part of the inner plexiform layer of connexin36 knockout mice suggests close association of these proteins with other structures in retina, possibly including gap junctions composed of an as-yet-unidentified connexin.
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Affiliation(s)
- C Ciolofan
- Department of Physiology, Faculty of Medicine, University of Manitoba, 730 William Avenue, Winnipeg, Manitoba, Canada R3E 3J7
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37
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Hawthorne SK, Busanelli RR, Kleene KC. The 5' UTR and 3' UTR of the sperm mitochondria-associated cysteine-rich protein mRNA regulate translation in spermatids by multiple mechanisms in transgenic mice. Dev Biol 2006; 297:118-26. [PMID: 16759650 DOI: 10.1016/j.ydbio.2006.04.468] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 04/28/2006] [Indexed: 01/09/2023]
Abstract
The Smcp mRNA encoding the sperm mitochondria-associated cysteine-rich protein is translationally repressed in round spermatids and translationally active in elongated spermatids. The patterns of transcription and translation of fusions of the Smcp promoter, the green fluorescent protein coding region (Gfp) and various combination of the Smcp and Gfp 5' UTR and 3' UTR have been studied in transgenic mice. 518 nt of Smcp 5' flanking region and 8 nt of 5' UTR drive transcription of mRNAs containing the Gfp coding region in early round spermatids at the same transcription start site as the natural Smcp gene. Transcripts containing both the Gfp 5' and 3' UTRs are translationally active in step 2 spermatids as detected by GFP fluorescence in squashes of living seminiferous tubules from adult testes, and the presence of polysomal mRNAs in sucrose gradient analyses of testes from 21-day-old prepubertal mice, which contain early round spermatids and lack elongated spermatids. By comparison, expression of GFP is delayed until steps 5 and 10, respectively, in transcripts containing the Smcp 5' UTR and Gfp 3' UTR and the Gfp 5' UTR and the Smcp 3' UTR. Sucrose gradient analysis of 21-day-old testes demonstrates that transcripts containing the Smcp 3' UTR exhibit a bimodal distribution in free-mRNPs and polysomes, indicating that the 3' UTR blocks the expression of GFP after the transcripts have entered the elongation phase, a mechanism that may involve microRNAs. The Smcp 5' UTR reduces the levels and size of polysomes in adult testis. In addition, the natural Smcp mRNA contains a positive control element that counteracts the inhibition of translation by the Smcp 5' UTR in adult testis, and the Smcp 3' UTR strongly localizes GFP fluorescence in step 10 spermatids.
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Affiliation(s)
- Sabrina K Hawthorne
- Department of Biology, University of Massachusetts-Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
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38
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Hogeveen KN, Sassone-Corsi P. Regulation of gene expression in post-meiotic male germ cells: CREM-signalling pathways and male fertility. HUM FERTIL 2006; 9:73-9. [PMID: 16825108 DOI: 10.1080/14647270500463400] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Spermatogenesis is a remarkably complex process in which diploid spermatogonial stem cells undergo a series of mitotic and meiotic cell divisions to give rise to haploid round spermatids. These haploid cells then go through a dramatic morphological remodelling involving extensive chromatin condensation, reduction in nuclear and cytoplasmic volume, formation of an acrosome system and tail, all of which contribute to the formation of a mature spermatozoon fully capable of fertilizing the oocyte and passing along its genetic information to the next generation. To accomplish such a complex program, an intricate and efficient mechanism is required to finely tune the levels of expression of specific genes necessary for this process. Accordingly, the regulation of gene expression in post-meiotic male germ cells is governed by specific mechanisms unique to these cells. The cyclic adenosine monophosphate (cAMP) response element modulator (CREM) is an essential component of this program, and its activity is regulated through interactions with a germ cell-specific, CREM phosphorylation-independent transcriptional co-activator, activator of CREM in testis (ACT). In turn, the ability of ACT to regulate CREM activity is controlled by a germ cell-specific kinesin, Kif17b, which regulates the subcellular distribution of ACT. Further, the mRNA from CREM target genes interacts with several germ cell-specific RNA-binding proteins, which function to transport and stabilize these mRNAs. This sophisticated and complex regulation of gene expression in post-meiotic germ cells is governed by unique mechanisms specific to these cells and is fundamental to male fertility.
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Affiliation(s)
- Kevin N Hogeveen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Strasbourg, France
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39
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Abstract
RNA-binding proteins play a major part in the control of gene expression during early development. At this stage, the majority of regulation occurs at the levels of translation and RNA localization. These processes are, in general, mediated by RNA-binding proteins interacting with specific sequence motifs in the 3'-untranslated regions of their target RNAs. Although initial work concentrated on the analysis of these sequences and their trans-acting factors, we are now beginning to gain an understanding of the mechanisms by which some of these proteins function. In this review, we will describe a number of different families of RNA-binding proteins, grouping them together on the basis of common regulatory strategies, and emphasizing the recurrent themes that occur, both across different species and as a response to different biological problems.
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Lu ZH, Books JT, Ley TJ. YB-1 is important for late-stage embryonic development, optimal cellular stress responses, and the prevention of premature senescence. Mol Cell Biol 2005; 25:4625-37. [PMID: 15899865 PMCID: PMC1140647 DOI: 10.1128/mcb.25.11.4625-4637.2005] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proteins containing "cold shock" domains belong to the most evolutionarily conserved family of nucleic acid-binding proteins known among bacteria, plants, and animals. One of these proteins, YB-1, is widely expressed throughout development and has been implicated as a cell survival factor that regulates the transcription and/or translation of many cellular growth and death-related genes. For these reasons, YB-1 deficiency has been predicted to be incompatible with cell survival. However, the majority of YB-1(-/-) embryos develop normally up to embryonic day 13.5 (E13.5). After E13.5, YB-1(-/-) embryos exhibit severe growth retardation and progressive mortality, revealing a nonredundant role of YB-1 in late embryonic development. Fibroblasts derived from YB-1(-/-) embryos displayed a normal rate of protein synthesis and minimal alterations in the transcriptome and proteome but demonstrated reduced abilities to respond to oxidative, genotoxic, and oncogene-induced stresses. YB-1(-/-) cells under oxidative stress expressed high levels of the G(1)-specific CDK inhibitors p16Ink4a and p21Cip1 and senesced prematurely; this defect was corrected by knocking down CDK inhibitor levels with specific small interfering RNAs. These data suggest that YB-1 normally represses the transcription of CDK inhibitors, making it an important component of the cellular stress response signaling pathway.
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Affiliation(s)
- Zhi Hong Lu
- Division of Oncology, Department of Medicine, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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41
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Shi HJ, Wu AZ, Santos M, Feng ZM, Huang L, Chen YM, Zhu K, Chen CLC. Cloning and characterization of rat spermatid protein SSP411: a thioredoxin-like protein. ACTA ACUST UNITED AC 2005; 25:479-93. [PMID: 15223837 DOI: 10.1002/j.1939-4640.2004.tb02819.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In an attempt to identify new sperm-specific genes that are involved in sperm maturation, fertilization, and embryo development, such as the mammalian ortholog of the sperm-supplied protein gene, spe-11, in Caenorhabditis elegans, we cloned and characterized a new spermatid-specific protein gene, ssp411, from adult rat testes. The ssp411 cDNA shared >85% sequence identity with an unnamed human protein, FLJ21347, and an uncharacterized mouse testicular protein called transcript increased in spermiogenesis 78 (TISP78). A 2.8-kb ssp411 mRNA was expressed in a testis-specific and age-dependent manner; the mRNA was evident at 28 days and remained at high levels throughout adulthood. An SSP411 protein of molecular weight 88 000 was detected in testicular extracts by Western blot analysis. Ssp411 mRNA and SSP411 protein, as analyzed by in situ hybridization and immunohistochemistry, were both expressed in a stage-dependent fashion during the cycle of the seminiferous epithelium. The ssp411 mRNA was predominantly localized to round and elongated spermatids, with maximal expression at stages VII-XII. The SSP411 protein was mainly observed in elongated spermatids and reached its highest levels during stages V-VI. A conserved thioredoxin-like domain was detected in the N-terminal region of SSP411 and its orthologs. An analysis of the predicted 3-dimensional structural modeling and folding pattern further suggested that SSP411 is identifiable as a member of thioredoxin family. In summary, we have identified a new rat spermatid protein gene, ssp411, and its orthologs in human and mouse and demonstrated that SSP411 might belong to a testis-specific thioredoxin family. This suggests that SSP411 may play a role in sperm maturation, fertilization, and/or embryo development, as has been shown in thioredoxin family.
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Affiliation(s)
- Hui-Juan Shi
- Center for Biomedical Research, Population Council, Beijing, P.R. China
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42
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Iida H, Ichinose J, Kaneko T, Mōri T, Shibata Y. Complementary DNA cloning of rat spetex-1, a spermatid-expressing gene-1, encoding a 63 kDa cytoplasmic protein of elongate spermatids. Mol Reprod Dev 2005; 68:385-93. [PMID: 15236321 DOI: 10.1002/mrd.20101] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We used differential display in combination with complementary DNA (cDNA) cloning approach to isolate a novel rat gene designated as spetex-1, which had an open reading frame of 1,668-length nucleotides encoding a protein of 556 amino acids. Spetex-1 mRNA was highly expressed in testis, and weekly expressed in lung, intestine, and spleen. Spetex-1 expression in the rat testes was detected first at 3 weeks in postnatal development and continued to be detected up to adulthood. A search in the databases showed that the amino acid sequence of spetex-1 was 82% identical to that of its mouse homologue found in the databases. Both rat spetex-1 and the mouse homologue contained Ser-X (X = His, Arg, or Asn) repeats in the middle portion of the proteins. In situ hybridization revealed that spetex-1 mRNA was expressed in haploid spermatids of step 7-18 within the seminiferous epithelium. Immunohistochemical analysis with confocal laser-scanning microscopy demonstrated that spetex-1 protein was not expressed in spermatogonia, spermatocytes, and round spermatids in adult rat testis, but was specifically detected in the residual cytoplasm of elongate spermatids of step 15-18 as well as in residual bodies engulfed by Sertoli cells. We interpreted these data as a potential role of spetex-1 in spermatogenesis, especially in cell differentiation from late elongate spermatids to mature spermatozoa.
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Affiliation(s)
- Hiroshi Iida
- Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, Higashiku Hakozaki, Fukuoka, Japan.
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Abstract
Post-transcriptional mechanisms play an important role in the biology of germ cells, where they control key developmental decisions in cell division, differentiation and death. Because these post-transcriptional controls are cell-type-specific, and often utilize germ-cell-specific RNA-binding proteins, they provide useful diagnostic markers for male infertility and testicular cancer. Investigation of the genetics of male infertility in men and model organisms suggests that disruption of post-transcriptional control mechanisms can cause specific germ cell pathologies, and these studies point to future possible therapeutic routes for restoring spermatogenesis.
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Human Genetics, International Centre for Life, Central Parkway, Newcastle NE1 3BZ, UK
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Shirley CR, Hayashi S, Mounsey S, Yanagimachi R, Meistrich ML. Abnormalities and reduced reproductive potential of sperm from Tnp1- and Tnp2-null double mutant mice. Biol Reprod 2004; 71:1220-9. [PMID: 15189834 DOI: 10.1095/biolreprod.104.029363] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Previous studies have demonstrated the importance of transition nuclear proteins, TP1 and TP2, in spermatogenesis and male fertility. However, importance of the overall level of transition proteins and their level of redundancy in the production of normal sperm is not clear. Epididymal sperm from the nine possible Tnp1 and Tnp2 null genotypes demonstrated a general decrease in normal morphology, motility, chromatin condensation, and degree of protamine 2 processing with decreasing levels of transition proteins in mutant sperm. Nuclei of some mutant epididymal sperm stained poorly with hematoxylin and DNA fluorochromes, suggesting that the DNA of these sperm underwent degradation during epididymal transport. When epididymal sperm were injected directly into oocytes, fertilization and embryonic development were reduced only in the two most severely affected genotypes. These phenotypes indicated some functional redundancy of transition proteins; however, redundancy of transition protein function was not complete, as, for example, sperm from double heterozygous males had fewer abnormalities than sperm from males homozygous for a single Tnp null mutation. Our study suggests that each TP fulfills some unique function during spermiogenesis even though sperm phenotypes strongly indicate defects are largely attributable to an overall gene dosage effect. Similarities between sperm defects found in Tnp mutants and infertile patients make the Tnp mutants a valuable tool with which to study outcomes following fertilization using sperm with compromised DNA integrity.
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Affiliation(s)
- Cynthia R Shirley
- Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Zhao M, Shirley CR, Hayashi S, Marcon L, Mohapatra B, Suganuma R, Behringer RR, Boissonneault G, Yanagimachi R, Meistrich ML. Transition nuclear proteins are required for normal chromatin condensation and functional sperm development. Genesis 2004; 38:200-13. [PMID: 15083521 DOI: 10.1002/gene.20019] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The histone-to-protamine transition is important in the formation of spermatozoa. In mammals this involves two steps: replacement of histones by transition nuclear proteins (TPs) and replacement of TPs by protamines. To determine the functions of the TPs and their importance for sperm development, we generated mice lacking both TPs, since mice lacking only TP1 or TP2 were fertile. Our results indicated that TP1 and TP2 had partially complemented each other. In mice lacking both TPs, nuclear shaping, transcriptional repression, histone displacement, and protamine deposition proceeded relatively normally, but chromatin condensation was irregular in all spermatids, many late spermatids showed DNA breaks, and protamine 2 was not posttranslationally processed. Nevertheless, genomic integrity was maintained in mature spermatids, since efficient fertilization and production of offspring were achieved by intracytoplasmic sperm injection. However, many mature spermatids were retained in the testis, epididymal spermatozoa were drastically reduced in number and were highly abnormal, and the mice were sterile. Most epididymal spermatozoa were incapable of fertilization even using intracytoplasmic sperm injection. Thus, in mammals TPs are required for normal chromatin condensation, for reducing the number of DNA breaks, and for preventing the formation of secondary defects in spermatozoa, eventual loss of genomic integrity, and sterility.
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Affiliation(s)
- Ming Zhao
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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Shima JE, McLean DJ, McCarrey JR, Griswold MD. The murine testicular transcriptome: characterizing gene expression in the testis during the progression of spermatogenesis. Biol Reprod 2004; 71:319-30. [PMID: 15028632 DOI: 10.1095/biolreprod.103.026880] [Citation(s) in RCA: 403] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
One of the most promising applications of microarrays is the study of changes in gene expression associated with the growth and development of mammalian tissues. The testis provides an excellent model to determine the ability of microarrays to effectively characterize the changes in gene expression as an organ develops from birth to adulthood. To this end, a developmental testis gene expression time course profiling the expression patterns of approximately 36 000 transcripts on the Affymetrix MGU74v2 GeneChip platform at 11 distinct time points was created to gain a greater understanding of the molecular changes necessary for and elicited by the development of the testis. Additionally, gene expression profiles of isolated testicular cell types were created that can aid in the further characterization of the specific functional actions of each cell type in the testis. Statistical analysis of the data revealed 11 252 transcripts (9846 unique) expressed differentially in a significant manner. Subsequent cluster analysis produced five distinct expressional patterns within the time course. These patterns of expression are present at distinct chronological periods during testis development and often share similarities with cell-specific expression profiles. Analysis of cell-specific expression patterns produced unique and characteristic groups of transcripts that provide greater insight into the activities, biological and chronological, of testicular cell types during the progression of spermatogenesis. Further analysis of this time course can provide a distinct and more definitive view into the genes implicated, known and unknown, in the maturation, maintenance, and function of the testis and the integrated process of spermatogenesis.
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Affiliation(s)
- James E Shima
- Center for Reproductive Biology, School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
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Chennathukuzhi V, Morales CR, El-Alfy M, Hecht NB. The kinesin KIF17b and RNA-binding protein TB-RBP transport specific cAMP-responsive element modulator-regulated mRNAs in male germ cells. Proc Natl Acad Sci U S A 2003; 100:15566-71. [PMID: 14673085 PMCID: PMC307608 DOI: 10.1073/pnas.2536695100] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Testis brain RNA-binding protein (TB-RBP), the mouse orthologue of the human protein Translin, is a widely expressed and highly conserved protein with proposed functions in chromosomal translocations, mitotic cell division, and mRNA transport, stabilization, and storage. Targeted inactivation of TB-RBP leads to abnormalities in fertility and behavior. A testis-enriched kinesin KIF17b coimmunoprecipitates with TB-RBP in a RNA-protein complex containing specific cAMP-responsive element modulator (CREM)-regulated mRNAs. The specificity of this interaction is confirmed by in vivo RNA-protein crosslinking and transfections of hippocampal neurons. Combining in situ hybridization and immunohistochemistry at the electron microscope level, a temporally sequential dissociation of KIF17b and TB-RBP from specific mRNAs is detected with TB-RBP release coincident with the time of mRNA translation, indicating a separation of the processes of transport and translation. We conclude that KIF17b serves as a molecular motor component of a TB-RBP-mouse ribonucleoprotein complex transporting a group of specific CREM-regulated mRNAs in mammalian male postmeiotic germ cells. Because KIF17b has been reported to control CREM-dependent transcription in male germ cells by regulating the intracellular location of the transcriptional coactivator activator of CREM in testis, this indicates that one kinesin links the processes of transcription and transport of specific mRNAs in mammalian male germ cells.
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Affiliation(s)
- Vargheese Chennathukuzhi
- Center for Research on Reproduction and Women's Health, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6142, USA
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Kleene KC, Cataldo L, Mastrangelo MA, Tagne JB. Alternative patterns of transcription and translation of the ribosomal protein L32 mRNA in somatic and spermatogenic cells in mice. Exp Cell Res 2003; 291:101-10. [PMID: 14597412 DOI: 10.1016/s0014-4827(03)00339-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The patterns of transcription and translation of the ribosomal protein L32 (Rpl32) mRNA differ greatly in adult testis and somatic tissues. Northern blots reveal that the levels of Rpl32 mRNA are four- to five-fold higher in prepubertal and adult testes, and purified pachytene spermatocytes and round spermatids than in a variety of nongrowing adult somatic tissues. 5' RACE demonstrates that transcription in 8-day prepubertal testis, which lacks meiotic and haploid cells, strongly prefers the same start site in the 5' terminal oligopyrimidine tract (5' TOP) that is used is somatic cells. The 5' TOP is a cis element that inhibits translation of many mRNAs in nongrowing somatic cells. Although the sizes of deadenylated Rpl32 mRNAs are indistinguishable in somatic and spermatogenic cells, transcription initiates at 11 sites over a 31-nt segment in adult testis and approximately 62% of Rpl32 mRNAs lack a 5' TOP. In agreement with previous studies, low levels of cycloheximide increase the proportions and sizes of polysomes in absorbance profiles, and increase the proportions and sizes of polysomes translating four 5' TOP mRNA species including the Rpl32 mRNA in 8-day seminiferous tubules. In contrast, cycloheximide has little or no effect on the absorbance profiles and distribution of Rpl32 mRNA and 5' TOP mRNAs in adult seminiferous tubules. The failure of cycloheximide to increase the size of polysomes in adult seminiferous tubules implies a block in the pathway by which ribosomes are recruited onto translationally active mRNAs.
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Affiliation(s)
- Kenneth C Kleene
- Department of Biology, University of Massachusetts Boston, 100 Morrissey Boulevard, Boston, MA 02125-3393, USA.
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Abstract
Many crucial decisions, such as the location and timing of cell division, cell-fate determination, and embryonic axes establishment, are made in the early embryo, a time in development when there is often little or no transcription. For this reason, the control of variation in gene expression in the early embryo often relies on post-transcriptional control of maternal genes. Although the early embryo is rife with translational control, controlling mRNA activity is also important in other developmental processes, such as stem-cell proliferation, sex determination, neurogenesis and erythropoiesis.
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Affiliation(s)
- Scott Kuersten
- Laboratory of Genetics, University of Wisconsin-Madison, 445 Henry Mall, Madison, Wisconsin 53706, USA.
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Cho C, Jung-Ha H, Willis WD, Goulding EH, Stein P, Xu Z, Schultz RM, Hecht NB, Eddy EM. Protamine 2 deficiency leads to sperm DNA damage and embryo death in mice. Biol Reprod 2003; 69:211-7. [PMID: 12620939 DOI: 10.1095/biolreprod.102.015115] [Citation(s) in RCA: 244] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Cytokinesis is incomplete in spermatogenic cells, and the descendants of each stem cell form a clonal syncytium. As a result, a heterozygous mutation in a gene expressed postmeiotically affects all of the haploid spermatids within a syncytium. Previously, we have found that disruption of one copy of the gene for either protamine 1 (PRM1) or protamine 2 (PRM2) in the mouse results in a reduction in the amount of the respective protein, abnormal processing of PRM2, and inability of male chimeras to transmit either the mutant or wild-type allele derived from the 129-genotype embryonic stem cells to the next generation. Although it is believed that protamines are essential for compaction of the sperm nucleus and to protect the DNA from damage, this has not been proven experimentally. To test the hypothesis that failure of chimeras to transmit the 129 genotype to offspring was due to alterations in the organization and integrity of sperm DNA, we used the single-cell DNA electrophoresis (comet) assay, ultrastructural analysis, and the intracytoplasmic sperm injection (ICSI) procedure. Comet assay demonstrated a direct correlation between the fraction of sperm with haploinsufficiency of PRM2 and the frequency of sperm with damaged DNA. Ultrastructural analysis revealed reduced compaction of the chromatin. ICSI with PRM2-deficient sperm resulted in activation of most metaphase II-arrested mouse eggs, but few were able to develop to the blastocyst stage. These findings suggest that development fails because of damage to paternal DNA and that PRM2 is crucial for maintaining the integrity of sperm chromatin.
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Affiliation(s)
- Chunghee Cho
- Department of Life Science, Kwangju Institute of Science and Technology (K-JIST), Kwangju 500-712, Republic of Korea
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