The Mouse Polyubiquitin Gene Ubb Is Essential for Meiotic Progression

ABSTRACT Ubiquitin is encoded in mice by two polyubiquitin genes, Ubb and Ubc, that are considered to be stress inducible and two constitutively expressed monoubiquitin (Uba) genes. Here we report that targeted disruption of Ubb results in male and female infertility due to failure of germ cells to progress through meiosis I and hypogonadism. In the absence of Ubb, spermatocytes and oocytes arrest during meiotic prophase, before metaphase of the first meiotic division. Although cellular ubiquitin levels are believed to be maintained by a combination of functional redundancy among the four ubiquitin genes, stress inducibility of the two polyubiquitin genes, and ubiquitin recycling by proteasome-associated isopeptidases, our results indicate that ubiquitin is required for and consumed during meiotic progression. The striking similarity of the meiotic phenotype in Ubb −/− germ cells to the sporulation defect in fission yeast (Schizosaccharomyces pombe) lacking a polyubiquitin gene suggests that a meiotic role of the polyubiquitin gene has been conserved throughout eukaryotic evolution.

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Phosphorylation of the Anaphase Promoting Complex activator CDH1/FZR regulates the transition from Meiosis I to Meiosis II in mouse male germ cell

10.1101/2020.03.13.990127 ◽

2020 ◽

Author(s):

Nobuhiro Tanno ◽

Shinji Kuninaka ◽

Sayoko Fujimura ◽

Kaho Okamura ◽

Kazumasa Takemoto ◽

...

Keyword(s):

Cell Cycle ◽

Germ Cells ◽

Critical Role ◽

Biological Significance ◽

Mitotic Cell ◽

Anaphase Promoting Complex ◽

Meiosis I

SummaryCDH1/FZR is an activator of Anaphase promoting complex/Cyclosome (APC/C), best known for its role as E3 ubiquitin ligase that drives the cell cycle. APC/C activity is regulated by CDK-mediated phosphorylation of CDH1 during mitotic cell cycle. Although the critical role of CDH1 phosphorylation has been shown mainly in yeast and in vitro cell culture studies, its biological significance in mammalian tissues in vivo remained elusive. Here, we examined the in vivo role of CDH1 phosphorylation using a mouse model, in which non-phosphorylatable substitutions were introduced in the putative CDK-phosphorylation sites of CDH1. Although ablation of CDH1 phosphorylation did not show substantial consequences in mouse somatic tissues, it led to severe testicular defects resulting in male infertility. In the absence of CDH1 phosphorylation, male juvenile germ cells entered meiosis normally but skipped meiosis II producing diploid spermatid-like cells. In aged testis, male germ cells were overall abolished, showing Sertoli cell-only phenotype. The present study demonstrated that phosphorylation of CDH1 is required for temporal regulation of APC/C activity at the transition from meiosis I to meiosis II, and for spermatoginial stem cell maintenance, which raised an insight into the sexual dimorphism of CDH1-regulation in germ cells.

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SH2-B Is Required for Both Male and Female Reproduction

Molecular and Cellular Biology ◽

10.1128/mcb.22.9.3066-3077.2002 ◽

2002 ◽

Vol 22 (9) ◽

pp. 3066-3077 ◽

Cited By ~ 49

Author(s):

Satoshi Ohtsuka ◽

Satoshi Takaki ◽

Masanori Iseki ◽

Kanta Miyoshi ◽

Naomi Nakagata ◽

...

Keyword(s):

Growth Factors ◽

Follicle Stimulating Hormone ◽

Critical Role ◽

Cumulus Cells ◽

Female Reproduction ◽

Targeted Disruption ◽

Male And Female ◽

Factor I ◽

Igf I

ABSTRACT Many growth factors and hormones modulate the reproductive status in mammals. Among these, insulin and insulin-like growth factor I (IGF-I) regulate the development of gonadal tissues. SH2-B has been shown to interact with insulin and IGF-I receptors, although the role of SH2-B in these signals has not been clarified. To investigate the role of SH2-B, we generated mice with a targeted disruption of the SH2-B gene. Both male and female SH2-B−/− mice showed slight retardation in growth and impaired fertility. Female knockout mice possess small, anovulatory ovaries with reduced numbers of follicles and male SH2-B−/− mice have small testes with a reduced number of sperm. SH2-B−/− cumulus cells do not respond to either follicle-stimulating hormone or IGF-I. These data suggest that SH2-B plays a critical role in the IGF-I-mediated reproductive pathway in mice.

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The cohesin release factor Wapl interacts with Bub3 to govern SAC activity in female meiosis I

Science Advances ◽

10.1126/sciadv.aax3969 ◽

2020 ◽

Vol 6 (15) ◽

pp. eaax3969

Author(s):

Changyin Zhou ◽

Yilong Miao ◽

Zhaokang Cui ◽

Xiayan ShiYang ◽

Yu Zhang ◽

...

Keyword(s):

Spindle Assembly Checkpoint ◽

Mass Spectrometry Analysis ◽

Female Meiosis ◽

Spectrometry Analysis ◽

Binding Partner ◽

Meiotic Progression ◽

Cohesin Subunit ◽

Normal Meiosis ◽

Meiosis I

During mitotic prophase, cohesins are removed from chromosome arms by Wapl to ensure faithful sister chromatid separation. However, during female meiosis I, the resolution of chiasmata requires the proteolytic cleavage of cohesin subunit Rec8 along chromosome arms by Separase to separate homologs, and thus the role of Wapl remained unknown. Here, we report that Wapl functions as a regulator of spindle assembly checkpoint (SAC) to prevent aneuploidy in meiosis I. Depletion of Wapl accelerates meiotic progression, inactivates SAC, and causes meiotic defects such as aberrant spindle/chromosome structure and incorrect kinetochore-microtubule (K-MT) attachment, consequently leading to aneuploid eggs. Notably, we identify Bub3 as a binding partner of Wapl by immunoprecipitation and mass spectrometry analysis. We further determine that Wapl controls the SAC activity by maintaining Bub3 protein level and document that exogenous Bub3 restores the normal meiosis in Wapl-depleted oocytes. Together, our findings uncover unique, noncanonical roles for Wapl in mediating control of the SAC in female meiosis I.

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The essential role of Dnmt1 in gametogenesis in the large milkweed bug Oncopeltus fasciatus

10.1101/2020.07.23.218180 ◽

2020 ◽

Author(s):

Joshua T. Washington ◽

Katelyn R. Cavender ◽

Ashley U. Amukamara ◽

Elizabeth C. McKinney ◽

Robert J. Schmitz ◽

...

Keyword(s):

Dna Methylation ◽

Transcriptional Regulation ◽

Germ Cells ◽

Dna Methyltransferase ◽

Essential Role ◽

Oncopeltus Fasciatus ◽

Male And Female ◽

Taxonomic Groups ◽

Female Gametogenesis

AbstractGiven the importance of DNA methylation in protection of the genome against transposable elements and transcriptional regulation in other taxonomic groups, the diversity in both levels and patterns of DNA methylation in the insects raises questions about its function and evolution. We show that the maintenance DNA methyltransferase, DNMT1, affects meiosis and is essential to fertility in milkweed bugs, Oncopeltus fasciatus, while DNA methylation is not required in somatic cells. Our results support the hypothesis that Dnmt1 is required for the transition of germ cells to gametes in O. fasciatus and that this function is conserved in male and female gametogenesis. They further suggest that DNMT1 has a function independent of DNA methylation in germ cells. Our results raise the question of how a gene so critical in fitness across multiple insect species can have diverged widely across the insect tree of life.

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MicroRNA-202 safeguards meiotic progression by preventing premature degradation of REC8 mediated by separase

10.1101/2021.04.14.439735 ◽

2021 ◽

Author(s):

Jian Chen ◽

Chenxu Gao ◽

Chunwei Zheng ◽

Xiwen Lin ◽

Yan Ning ◽

...

Keyword(s):

Germ Cells ◽

Sister Chromatid ◽

Developmental Process ◽

Developmental Processes ◽

Meiotic Progression ◽

Multiple Processes ◽

Direct Target ◽

Meiosis I

AbstractMicroRNAs (miRNAs) are believed to play important roles in mammalian spermatogenesis but the in vivo functions of single miRNAs in this highly complex developmental process remain unclear. Here, we reported that miR-202, a member of the let-7 family, played an important role in mouse spermatogenesis by phenotypic evaluation of miR-202 knockout (KO) mice. In miR-202 KO mice, germ cells underwent apoptosis. Multiple processes in meiosis I including synapsis and crossover formation were disrupted, and inter-sister chromatid synapses were detected. More importantly, we found that upon miR-202 KO, meiotic-specific cohesin protein REC8 was prematurely cleaved by precociously activated separase, whose mRNA was a direct target of miR-202-3p. Our findings identify miR-202 as a novel regulator of meiosis and contribute to the list of miRNAs that play specific and important roles in developmental processes.

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The essential role of Dnmt1 in gametogenesis in the large milkweed bug Oncopeltus fasciatus

eLife ◽

10.7554/elife.62202 ◽

2021 ◽

Vol 10 ◽

Author(s):

Joshua T Washington ◽

Katelyn R Cavender ◽

Ashley U Amukamara ◽

Elizabeth C McKinney ◽

Robert J Schmitz ◽

...

Keyword(s):

Dna Methylation ◽

Transcriptional Regulation ◽

Germ Cells ◽

Dna Methyltransferase ◽

Essential Role ◽

Oncopeltus Fasciatus ◽

Male And Female ◽

Taxonomic Groups ◽

Female Gametogenesis

Given the importance of DNA methylation in protection of the genome against transposable elements and transcriptional regulation in other taxonomic groups, the diversity in both levels and patterns of DNA methylation in the insects raises questions about its function and evolution. We show that the maintenance DNA methyltransferase, DNMT1, affects meiosis and is essential to fertility in milkweed bugs, Oncopeltus fasciatus, while DNA methylation is not required in somatic cells. Our results support the hypothesis that Dnmt1 is required for the transition of germ cells to gametes in O. fasciatus and that this function is conserved in male and female gametogenesis. They further suggest that DNMT1 has a function independent of DNA methylation in germ cells. Our results raise the question of how a gene so critical in fitness across multiple insect species can have diverged widely across the insect tree of life.

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SYMPK Is Required for Meiosis and Involved in Alternative Splicing in Male Germ Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.715733 ◽

2021 ◽

Vol 9 ◽

Author(s):

Rui Wu ◽

Junfeng Zhan ◽

Bo Zheng ◽

Zhen Chen ◽

Jianbo Li ◽

...

Keyword(s):

Alternative Splicing ◽

Germ Cells ◽

Strand Break ◽

Rna Seq ◽

Male Germ Cells ◽

Meiotic Progression ◽

Chromosome Synapsis ◽

Dna Double Strand Break ◽

Nascent Transcripts

SYMPK is a scaffold protein that supports polyadenylation machinery assembly on nascent transcripts and is also involved in alternative splicing in some mammalian somatic cells. However, the role of SYMPK in germ cells remains unknown. Here, we report that SYMPK is highly expressed in male germ cells, and germ cell-specific knockout (cKO) of Sympk in mouse leads to male infertility. Sympk cKODdx4–cre mice showed reduced spermatogonia at P4 and almost no germ cells at P18. Sympk cKOStra8–Cre spermatocytes exhibit defects in homologous chromosome synapsis, DNA double-strand break (DSB) repair, and meiotic recombination. RNA-Seq analyses reveal that SYMPK is associated with alternative splicing, besides regulating the expressions of many genes in spermatogenic cells. Importantly, Sympk deletion results in abnormal alternative splicing and a decreased expression of Sun1. Taken together, our results demonstrate that SYMPK is pivotal for meiotic progression by regulating pre-mRNA alternative splicing in male germ cells.

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Meiotic CENP-C is a shepherd: bridging the space between the centromere and the kinetochore in time and space

Essays in Biochemistry ◽

10.1042/ebc20190080 ◽

2020 ◽

Vol 64 (2) ◽

pp. 251-261

Author(s):

Jessica E. Fellmeth ◽

Kim S. McKim

Keyword(s):

Chromosome Segregation ◽

New Technologies ◽

Early Prophase ◽

Unique Role ◽

Kinetochore Assembly ◽

M Phase ◽

In Vivo Analysis ◽

Meiosis I

Abstract While many of the proteins involved in the mitotic centromere and kinetochore are conserved in meiosis, they often gain a novel function due to the unique needs of homolog segregation during meiosis I (MI). CENP-C is a critical component of the centromere for kinetochore assembly in mitosis. Recent work, however, has highlighted the unique features of meiotic CENP-C. Centromere establishment and stability require CENP-C loading at the centromere for CENP-A function. Pre-meiotic loading of proteins necessary for homolog recombination as well as cohesion also rely on CENP-C, as do the main scaffolding components of the kinetochore. Much of this work relies on new technologies that enable in vivo analysis of meiosis like never before. Here, we strive to highlight the unique role of this highly conserved centromere protein that loads on to centromeres prior to M-phase onset, but continues to perform critical functions through chromosome segregation. CENP-C is not merely a structural link between the centromere and the kinetochore, but also a functional one joining the processes of early prophase homolog synapsis to late metaphase kinetochore assembly and signaling.

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