Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
1.
Genes Dev ; 38(3-4): 115-130, 2024 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-38383062

RESUMO

H3K9 trimethylation (H3K9me3) plays emerging roles in gene regulation, beyond its accumulation on pericentric constitutive heterochromatin. It remains a mystery why and how H3K9me3 undergoes dynamic regulation in male meiosis. Here, we identify a novel, critical regulator of H3K9 methylation and spermatogenic heterochromatin organization: the germline-specific protein ATF7IP2 (MCAF2). We show that in male meiosis, ATF7IP2 amasses on autosomal and X-pericentric heterochromatin, spreads through the entirety of the sex chromosomes, and accumulates on thousands of autosomal promoters and retrotransposon loci. On the sex chromosomes, which undergo meiotic sex chromosome inactivation (MSCI), the DNA damage response pathway recruits ATF7IP2 to X-pericentric heterochromatin, where it facilitates the recruitment of SETDB1, a histone methyltransferase that catalyzes H3K9me3. In the absence of ATF7IP2, male germ cells are arrested in meiotic prophase I. Analyses of ATF7IP2-deficient meiosis reveal the protein's essential roles in the maintenance of MSCI, suppression of retrotransposons, and global up-regulation of autosomal genes. We propose that ATF7IP2 is a downstream effector of the DDR pathway in meiosis that coordinates the organization of heterochromatin and gene regulation through the spatial regulation of SETDB1-mediated H3K9me3 deposition.


Assuntos
Heterocromatina , Histonas , Masculino , Células Germinativas/metabolismo , Heterocromatina/genética , Heterocromatina/metabolismo , Histonas/metabolismo , Meiose/genética , Metilação , Animais , Camundongos
2.
Genes Cells ; 29(10): 797-807, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39119753

RESUMO

Meiosis is regulated in sexually dimorphic manners in mammals. In females, the commitment to and entry into meiosis are coordinated with the developmental program of oocytes. Female germ cells initiate meiosis within a short time window during the fetal period and then undergo meiotic arrest until puberty. However, the genetic mechanisms underlying the orchestration of oocyte development and meiosis to maximize the reproductive lifespan of mammalian females remain largely elusive. While meiotic initiation is regulated by a sexually common mechanism, where meiosis initiator and Stimulated by Retinoic Acid Gene 8 (STRA8) activate the meiotic genes, the female-specific mode of meiotic initiation is mediated by the interaction between retinoblastoma (RB) and STRA8. This review highlights the female-specific mechanisms of meiotic initiation and meiotic prophase progression in the context of oocyte development. Furthermore, the downstream pathway of the RB-STRA8 interaction that may regulate meiotic arrest will be discussed in the context of oocyte development, highlighting a potential genetic link between the female-specific mode of meiotic entry and meiotic arrest.


Assuntos
Meiose , Oócitos , Oogênese , Animais , Oócitos/metabolismo , Oócitos/citologia , Feminino , Meiose/genética , Humanos , Oogênese/genética , Mamíferos , Proteína do Retinoblastoma/metabolismo , Proteína do Retinoblastoma/genética
3.
PLoS Biol ; 20(6): e3001678, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35687590

RESUMO

Cells must adjust the expression levels of metabolic enzymes in response to fluctuating nutrient supply. For glucose, such metabolic remodeling is highly dependent on a master transcription factor ChREBP/MondoA. However, it remains elusive how glucose fluctuations are sensed by ChREBP/MondoA despite the stability of major glycolytic pathways. Here, we show that in both flies and mice, ChREBP/MondoA activation in response to glucose ingestion involves an evolutionarily conserved glucose-metabolizing pathway: the polyol pathway. The polyol pathway converts glucose to fructose via sorbitol. It has been believed that this pathway is almost silent, and its activation in hyperglycemic conditions has deleterious effects on human health. We show that the polyol pathway regulates the glucose-responsive nuclear translocation of Mondo, a Drosophila homologue of ChREBP/MondoA, which directs gene expression for organismal growth and metabolism. Likewise, inhibition of the polyol pathway in mice impairs ChREBP's nuclear localization and reduces glucose tolerance. We propose that the polyol pathway is an evolutionarily conserved sensing system for glucose uptake that allows metabolic remodeling.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Glucose , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Metabolismo dos Carboidratos , Drosophila/metabolismo , Glucose/metabolismo , Camundongos , Polímeros , Fatores de Transcrição/metabolismo
4.
PLoS Genet ; 18(6): e1010241, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35648791

RESUMO

Meiosis is a hallmark event in germ cell development that accompanies sequential events executed by numerous molecules. Therefore, characterization of these factors is one of the best strategies to clarify the mechanism of meiosis. Here, we report tripartite motif-containing 41 (TRIM41), a ubiquitin ligase E3, as an essential factor for proper meiotic progression and fertility in male mice. Trim41 knockout (KO) spermatocytes exhibited synaptonemal complex protein 3 (SYCP3) overloading, especially on the X chromosome. Furthermore, mutant mice lacking the RING domain of TRIM41, required for the ubiquitin ligase E3 activity, phenocopied Trim41 KO mice. We then examined the behavior of mutant TRIM41 (ΔRING-TRIM41) and found that ΔRING-TRIM41 accumulated on the chromosome axes with overloaded SYCP3. This result suggested that TRIM41 exerts its function on the chromosome axes. Our study revealed that Trim41 is essential for preventing SYCP3 overloading, suggesting a TRIM41-mediated mechanism for regulating chromosome axis protein dynamics during male meiotic progression.


Assuntos
Proteínas Nucleares , Complexo Sinaptonêmico , Ubiquitina-Proteína Ligases/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Masculino , Meiose/genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Espermatócitos/metabolismo , Complexo Sinaptonêmico/genética , Complexo Sinaptonêmico/metabolismo , Ubiquitina-Proteína Ligases/genética
5.
Development ; 148(10)2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33998651

RESUMO

Heterochromatin-related epigenetic mechanisms, such as DNA methylation, facilitate pairing of homologous chromosomes during the meiotic prophase of mammalian spermatogenesis. In pro-spermatogonia, de novo DNA methylation plays a key role in completing meiotic prophase and initiating meiotic division. However, the role of maintenance DNA methylation in the regulation of meiosis, especially in the adult, is not well understood. Here, we reveal that NP95 (also known as UHRF1) and DNMT1 - two essential proteins for maintenance DNA methylation - are co-expressed in spermatogonia and are necessary for meiosis in male germ cells. We find that Np95- or Dnmt1-deficient spermatocytes exhibit spermatogenic defects characterized by synaptic failure during meiotic prophase. In addition, assembly of pericentric heterochromatin clusters in early meiotic prophase, a phenomenon that is required for subsequent pairing of homologous chromosomes, is disrupted in both mutants. Based on these observations, we propose that DNA methylation, established in pre-meiotic spermatogonia, regulates synapsis of homologous chromosomes and, in turn, quality control of male germ cells. Maintenance DNA methylation, therefore, plays a role in ensuring faithful transmission of both genetic and epigenetic information to offspring.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/genética , Pareamento Cromossômico/genética , DNA (Citosina-5-)-Metiltransferase 1/genética , Metilação de DNA/genética , Espermatócitos/crescimento & desenvolvimento , Espermatogênese/genética , Ubiquitina-Proteína Ligases/genética , Células-Tronco Germinativas Adultas/citologia , Animais , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Epigênese Genética/genética , Heterocromatina/metabolismo , Masculino , Camundongos , Camundongos Knockout , Espermatócitos/fisiologia , Espermatogênese/fisiologia , Ubiquitina-Proteína Ligases/metabolismo
6.
Genes Cells ; 28(12): 831-844, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37778747

RESUMO

Mouse ES cell populations contain a minor sub-population that expresses genes specifically expressed in 2-cell stage embryos. This sub-population consists of 2-cell-gene labeled cells (2CLCs) generated by the transient activation of the 2-cell specific genes initiated by the master regulator, Dux. However, the mechanism regulating the transient expression remains largely unclear. Here we reported a novel function of Zfp352, one of the 2-cell specific genes, in regulating the 2CLC sub-population. Zfp352 encodes zinc-finger transcription factor belonging to the Klf family. Dux transiently activates Zfp352 after the activation of Zscan4c in a subset of the 2CLC subpopulation. Interestingly, in the reporter assay, the transcriptional activation of Zscan4c by Dux is strongly repressed by the co-expression of Zfp352. However, the knockout of Zfp352 resulted in the repression of a subset of the 2-cell-specific genes. These data suggest the dual roles of Zfp352 in regulating the transient activation of the 2-cell-specific genes.


Assuntos
Proteínas de Ligação a DNA , Células-Tronco Embrionárias Murinas , Fatores de Transcrição , Animais , Camundongos , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Embrionárias Murinas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Dedos de Zinco/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo
7.
Genes Cells ; 28(1): 15-28, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36371617

RESUMO

In mammals, primordial germ cells (PGCs) enter meiosis and differentiate into primary oocytes in embryonic ovaries. Previously, we demonstrated that meiotic gene induction and meiotic initiation were impaired in female germline cells of conditional knockout (CKO) mice lacking the Smarcb1 (Snf5) gene, which encodes a core subunit of the switching defective/sucrose non-fermenting (SWI/SNF) complex. In this study, we classified meiotic genes expressed at lower levels in Snf5 CKO females into two groups based on promoter accessibility. The promoters of 74% of these genes showed lower accessibility in mutant mice, whereas those of the remaining genes were opened without the SWI/SNF complex. Notably, the former genes included Meiosin, which encodes a transcriptional regulator essential for meiotic gene activation. The promoters of the former and the latter genes were mainly modified with H3K27me3/bivalent and H3K4me3 histone marks, respectively. A subset of the former genes was precociously activated in female PGCs deficient in polycomb repressive complexes (PRCs). Our results point to a mechanism through which the SWI/SNF complex coordinates meiotic gene activation via the remodeling of PRC-repressed genes, including Meiosin, in female germline cells.


Assuntos
Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona , Animais , Feminino , Camundongos , Cromatina , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Células Germinativas/metabolismo , Mamíferos/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional
9.
PLoS Genet ; 17(5): e1009412, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33961623

RESUMO

Meiosis is a cell division process with complex chromosome events where various molecules must work in tandem. To find meiosis-related genes, we screened evolutionarily conserved and reproductive tract-enriched genes using the CRISPR/Cas9 system and identified potassium channel tetramerization domain containing 19 (Kctd19) as an essential factor for meiosis. In prophase I, Kctd19 deficiency did not affect synapsis or the DNA damage response, and chiasma structures were also observed in metaphase I spermatocytes of Kctd19 KO mice. However, spermatocytes underwent apoptotic elimination during the metaphase-anaphase transition. We were able to rescue the Kctd19 KO phenotype with an epitope-tagged Kctd19 transgene. By immunoprecipitation-mass spectrometry, we confirmed the association of KCTD19 with zinc finger protein 541 (ZFP541) and histone deacetylase 1 (HDAC1). Phenotyping of Zfp541 KO spermatocytes demonstrated XY chromosome asynapsis and recurrent DNA damage in the late pachytene stage, leading to apoptosis. In summary, our study reveals that KCTD19 associates with ZFP541 and HDAC1, and that both KCTD19 and ZFP541 are essential for meiosis in male mice.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Genes Essenciais , Meiose , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Anáfase , Animais , Sistemas CRISPR-Cas/genética , Proteínas de Ciclo Celular/deficiência , Proteínas de Ciclo Celular/genética , Núcleo Celular/metabolismo , Proteínas Cromossômicas não Histona/deficiência , Proteínas Cromossômicas não Histona/genética , Pareamento Cromossômico , Sequência Conservada , Dano ao DNA , Evolução Molecular , Fertilidade/genética , Histona Desacetilase 1/metabolismo , Masculino , Prófase Meiótica I , Metáfase , Camundongos , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Estágio Paquíteno , Fenótipo , Espermátides/citologia , Espermatócitos/citologia , Espermatócitos/metabolismo , Testículo/metabolismo , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Transgenes
10.
Reproduction ; 165(5): 507-520, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36866926

RESUMO

In brief: Apart from mice, meiosis initiation factors and their transcriptional regulation mechanisms are largely unknown in mammals. This study suggests that STRA8 and MEIOSIN are both meiosis initiation factors in mammals, but their transcription is epigenetically regulated differently from each other. Abstract: In the mouse, the timing of meiosis onset differs between sexes due to the sex-specific regulation of the meiosis initiation factors, STRA8 and MEIOSIN. Before the initiation of meiotic prophase I, the Stra8 promoter loses suppressive histone-3-lysine-27 trimethylation (H3K27me3) in both sexes, suggesting that H3K27me3-associated chromatin remodelling may be responsible for activating STRA8 and its co-factor MEIOSIN. Here we examined MEIOSIN and STRA8 expression in a eutherian (the mouse), two marsupials (the grey short-tailed opossum and the tammar wallaby) and two monotremes (the platypus and the short-beaked echidna) to ask whether this pathway is conserved between all mammals. The conserved expression of both genes in all three mammalian groups and of MEIOSIN and STRA8 protein in therian mammals suggests that they are the meiosis initiation factors in all mammals. Analyses of published DNase-seq and chromatin-immunoprecipitation sequencing (ChIP-seq) data sets confirmed that H3K27me3-associated chromatin remodelling occurred at the STRA8, but not the MEIOSIN, promoter in therian mammals. Furthermore, culturing tammar ovaries with an inhibitor of H3K27me3 demethylation before meiotic prophase I affected STRA8 but not MEIOSIN transcriptional levels. Our data suggest that H3K27me3-associated chromatin remodelling is an ancestral mechanism that allows STRA8 expression in mammalian pre-meiotic germ cells.


Assuntos
Histonas , Meiose , Animais , Feminino , Masculino , Camundongos , Proteínas Adaptadoras de Transdução de Sinal/genética , Montagem e Desmontagem da Cromatina , Células Germinativas/metabolismo , Histonas/metabolismo , Mamíferos/genética , Tretinoína/metabolismo
11.
J Reprod Dev ; 69(3): 139-146, 2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-36927827

RESUMO

In mouse fetal gonads, germ cell development is accompanied by changes in cell cycle mode in response to external signals and intrinsic mechanisms of cells. During fetal development, male germ cells undergo G0/G1 arrest, while female germ cells exit the mitotic cell cycle and enter meiosis. In fetal testes, NANOS2 and CYP26B1 force germ cells to stay in G0/G1 arrest phase, preventing them from entering the meiotic cell cycle. In the fetal ovary, external signals, such as RA, BMP, and WNT, promote the competency of female germ cells to enter the meiotic cell cycle. MEIOSIN and STRA8 ensure the establishment of the meiotic cell cycle by activating meiotic genes, such that meiotic entry coincides with the S phase. This review discusses germ cell development from the viewpoint of cell cycle regulation and highlights the mechanism of the entry of germ cells into meiosis.


Assuntos
Células Germinativas , Tretinoína , Masculino , Feminino , Camundongos , Animais , Meiose , Testículo/metabolismo , Diferenciação Celular , Mamíferos/metabolismo
12.
PLoS Genet ; 16(2): e1008640, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32092049

RESUMO

Meiotic recombination is essential for faithful segregation of homologous chromosomes during gametogenesis. The progression of recombination is associated with dynamic changes in meiotic chromatin structures. However, whether Sycp2, a key structural component of meiotic chromatin, is required for the initiation of meiotic recombination is still unclear in vertebrates. Here, we describe that Sycp2 is required for assembly of the synaptonemal complex and early meiotic events in zebrafish spermatocytes. Our genetic screening by N-ethyl-N-nitrosourea mutagenesis revealed that ietsugu (its), a mutant zebrafish line with an aberrant splice site in the sycp2 gene, showed a defect during meiotic prophase I. The its mutation appeared to be a hypomorphic mutation compared to sycp2 knockout mutations generated by TALEN mutagenesis. Taking advantage of these sycp2 hypomorphic and knockout mutant lines, we demonstrated that Sycp2 is required for the assembly of the synaptonemal complex that is initiated in the vicinity of telomeres in wild-type zebrafish spermatocytes. Accordingly, homologous pairing, the foci of the meiotic recombinases Dmc1/Rad51 and RPA, and γH2AX signals were largely diminished in sycp2 knockout spermatocytes. Taken together, our data indicate that Sycp2 plays a critical role in not only the assembly of the synaptonemal complex, but also early meiotic recombination and homologous pairing, in vertebrates.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Recombinação Homóloga , Proteínas Nucleares/metabolismo , Espermatócitos/metabolismo , Complexo Sinaptonêmico/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/fisiologia , Animais , Animais Geneticamente Modificados , Proteínas de Ciclo Celular/genética , Técnicas de Inativação de Genes , Masculino , Mutação , Proteínas Nucleares/genética , Complexo Sinaptonêmico/genética , Proteínas de Peixe-Zebra/genética
13.
PLoS Genet ; 16(9): e1009048, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32931493

RESUMO

During meiotic prophase, sister chromatids are organized into axial element (AE), which underlies the structural framework for the meiotic events such as meiotic recombination and homolog synapsis. HORMA domain-containing proteins (HORMADs) localize along AE and play critical roles in the regulation of those meiotic events. Organization of AE is attributed to two groups of proteins: meiotic cohesins REC8 and RAD21L; and AE components SYCP2 and SYCP3. It has been elusive how these chromosome structural proteins contribute to the chromatin loading of HORMADs prior to AE formation. Here we newly generated Sycp2 null mice and showed that initial chromatin loading of HORMAD1 was mediated by meiotic cohesins prior to AE formation. HORMAD1 interacted not only with the AE components SYCP2 and SYCP3 but also with meiotic cohesins. Notably, HORMAD1 interacted with meiotic cohesins even in Sycp2-KO, and localized along cohesin axial cores independently of the AE components SYCP2 and SYCP3. Hormad1/Rad21L-double knockout (dKO) showed more severe defects in the formation of synaptonemal complex (SC) compared to Hormad1-KO or Rad21L-KO. Intriguingly, Hormad1/Rec8-dKO but not Hormad1/Rad21L-dKO showed precocious separation of sister chromatid axis. These findings suggest that meiotic cohesins REC8 and RAD21L mediate chromatin loading and the mode of action of HORMAD1 for synapsis during early meiotic prophase.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Animais , Cromátides/genética , Cromátides/metabolismo , Cromatina/metabolismo , Cromossomos/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Masculino , Meiose/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares/genética , Fosfoproteínas/genética , Prófase/genética , Espermatócitos/metabolismo , Complexo Sinaptonêmico/metabolismo , Coesinas
14.
Genes Cells ; 26(11): 874-890, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34418226

RESUMO

Nearly half of the human genome consists of repetitive sequences such as long interspersed nuclear elements. The relationship between these repeating sequences and diseases has remained unclear. Gene trapping is a useful technique for disrupting a gene and expressing a reporter gene by using the promoter activity of the gene. The analysis of trapped genes revealed a new genome element-the chromosome-specific clustered trap (CSCT) region. For any examined sequence within this region, an equivalent was found using the BLAT of the University of California, Santa Cruz (UCSC) Genome Browser. CSCT13 mapped to chromosome 13 and contained only three genes. To elucidate its in vivo function, the whole CSCT13 region (1.6 Mbp) was deleted using the CRISPR/Cas9 system in mouse embryonic stem cells, and subsequently, a CSCT13 knockout mouse line was established. The rate of homozygotes was significantly lower than expected according to Mendel's laws. In addition, the number of offspring obtained by mating homozygotes was significantly smaller than that obtained by crossing controls. Furthermore, CSCT13 might have an effect on meiotic homologous recombination. This study identifies a transcriptionally active CSCT with an important role in mouse development.


Assuntos
Genoma , Sequências Repetitivas de Ácido Nucleico , Animais , Sistemas CRISPR-Cas/genética , Cromossomos/genética , Genes Reporter , Camundongos , Software
15.
Genes Dev ; 28(6): 594-607, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24589552

RESUMO

During meiosis, homologous chromosome (homolog) pairing is promoted by several layers of regulation that include dynamic chromosome movement and meiotic recombination. However, the way in which homologs recognize each other remains a fundamental issue in chromosome biology. Here, we show that homolog recognition or association initiates upon entry into meiotic prophase before axis assembly and double-strand break (DSB) formation. This homolog association develops into tight pairing only during or after axis formation. Intriguingly, the ability to recognize homologs is retained in Sun1 knockout spermatocytes, in which telomere-directed chromosome movement is abolished, and this is the case even in Spo11 knockout spermatocytes, in which DSB-dependent DNA homology search is absent. Disruption of meiosis-specific cohesin RAD21L precludes the initial association of homologs as well as the subsequent pairing in spermatocytes. These findings suggest the intriguing possibility that homolog recognition is achieved primarily by searching for homology in the chromosome architecture as defined by meiosis-specific cohesin rather than in the DNA sequence itself.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Pareamento Cromossômico/fisiologia , Meiose/fisiologia , Espermatócitos/fisiologia , Animais , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Pareamento Cromossômico/genética , Cromossomos/metabolismo , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Feminino , Técnicas de Inativação de Genes , Hibridização in Situ Fluorescente , Masculino , Meiose/genética , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Espermatócitos/metabolismo , Coesinas
16.
Nature ; 517(7535): 466-71, 2015 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-25533956

RESUMO

The kinetochore is the crucial apparatus regulating chromosome segregation in mitosis and meiosis. Particularly in meiosis I, unlike in mitosis, sister kinetochores are captured by microtubules emanating from the same spindle pole (mono-orientation) and centromeric cohesion mediated by cohesin is protected in the following anaphase. Although meiotic kinetochore factors have been identified only in budding and fission yeasts, these molecules and their functions are thought to have diverged earlier. Therefore, a conserved mechanism for meiotic kinetochore regulation remains elusive. Here we have identified in mouse a meiosis-specific kinetochore factor that we termed MEIKIN, which functions in meiosis I but not in meiosis II or mitosis. MEIKIN plays a crucial role in both mono-orientation and centromeric cohesion protection, partly by stabilizing the localization of the cohesin protector shugoshin. These functions are mediated mainly by the activity of Polo-like kinase PLK1, which is enriched to kinetochores in a MEIKIN-dependent manner. Our integrative analysis indicates that the long-awaited key regulator of meiotic kinetochore function is Meikin, which is conserved from yeasts to humans.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Sequência Conservada , Cinetocoros/metabolismo , Meiose , Animais , Proteínas de Ciclo Celular/metabolismo , Centrômero/metabolismo , Proteínas Cromossômicas não Histona/deficiência , Proteínas Cromossômicas não Histona/genética , Feminino , Humanos , Infertilidade/genética , Infertilidade/metabolismo , Masculino , Camundongos , Dados de Sequência Molecular , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Quinase 1 Polo-Like
17.
Genes Cells ; 24(1): 6-30, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30479058

RESUMO

Cohesin is an evolutionary conserved multi-protein complex that plays a pivotal role in chromosome dynamics. It plays a role both in sister chromatid cohesion and in establishing higher order chromosome architecture, in somatic and germ cells. Notably, the cohesin complex in meiosis differs from that in mitosis. In mammalian meiosis, distinct types of cohesin complexes are produced by altering the combination of meiosis-specific subunits. The meiosis-specific subunits endow the cohesin complex with specific functions for numerous meiosis-associated chromosomal events, such as chromosome axis formation, homologue association, meiotic recombination and centromeric cohesion for sister kinetochore geometry. This review mainly focuses on the cohesin complex in mammalian meiosis, pointing out the differences in its roles from those in mitosis. Further, common and divergent aspects of the meiosis-specific cohesin complex between mammals and other organisms are discussed.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Mamíferos/metabolismo , Meiose , Animais , Pareamento Cromossômico , Cromossomos de Mamíferos/metabolismo , Mitose , Coesinas
18.
Genes Dev ; 24(19): 2169-79, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20889715

RESUMO

Shugoshin (Sgo) is a conserved centromeric protein. Mammalian Sgo1 collaborates with protein phosphatase 2A (PP2A) to protect mitotic cohesin from the prophase dissociation pathway. Although another shugoshin-like protein, Sgo2, is required for the centromeric protection of cohesion in germ cells, its precise molecular function remains largely elusive. We demonstrate that hSgo2 plays a dual role in chromosome congression and centromeric protection of cohesion in HeLa cells, while the latter function is exposed only in perturbed mitosis. These functions partly overlap with those of Aurora B, a kinase setting faithful chromosome segregation. Accordingly, we identified the phosphorylation of hSgo2 by Aurora B at the N-terminal coiled-coil region and the middle region, and showed that these phosphorylations separately promote binding of hSgo2 to PP2A and MCAK, factors required for centromeric protection and chromosome congression, respectively. Furthermore, these phosphorylations are essential for localizing PP2A and MCAK to centromeres. This mechanism seems applicable to germ cells as well. Thus, our study identifies Sgo2 as a hitherto unknown crucial cellular substrate of Aurora B in mammalian cells.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Centrômero/metabolismo , Cinesinas/metabolismo , Proteína Fosfatase 2/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Aurora Quinase B , Aurora Quinases , Células Cultivadas , Células HeLa , Humanos , Fosforilação , Transporte Proteico
19.
J Cell Sci ; 128(9): 1800-11, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25795304

RESUMO

The formation of programmed DNA double-strand breaks (DSBs) at the beginning of meiotic prophase marks the initiation of meiotic recombination. Meiotic DSB formation is catalyzed by SPO11 and their repair takes place on meiotic chromosome axes. The evolutionarily conserved MEI4 protein is required for meiotic DSB formation and is localized on chromosome axes. Here, we show that HORMAD1, one of the meiotic chromosome axis components, is required for MEI4 localization. Importantly, the quantitative correlation between the level of axis-associated MEI4 and DSB formation suggests that axis-associated MEI4 could be a limiting factor for DSB formation. We also show that MEI1, REC8 and RAD21L are important for proper MEI4 localization. These findings on MEI4 dynamics during meiotic prophase suggest that the association of MEI4 to chromosome axes is required for DSB formation, and that the loss of this association upon DSB repair could contribute to turning off meiotic DSB formation.


Assuntos
Quebras de DNA de Cadeia Dupla , Meiose , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Pareamento Cromossômico , Cromossomos de Mamíferos/metabolismo , Prófase Meiótica I , Camundongos , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Subunidades Proteicas/metabolismo , Transporte Proteico , Fatores de Tempo , Coesinas
20.
J Biochem ; 2024 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-39446564

RESUMO

The nuclear envelope (NE) is a double-membrane structure critical for genome maintenance and cellular function, composed of the inner and outer nuclear membranes. In fission yeast, the inner nuclear membrane (INM) proteins Lem2 and Bqt4 are essential for maintaining NE integrity. The study published by Hiraoka group (Hirano et al. 2023) explores the interactions between Lem2 and Bqt4 with lipid synthesis enzymes, addressing their roles in NE maintenance. The authors identified Lem2- and Bqt4-binding proteins using immunoprecipitation and mass spectrometry, revealing that Lem2 interacts with lipid synthesis enzymes, while Bqt4 binds to an enzyme that involves in glucosylceramide synthesis. These findings suggest that Lem2 and Bqt4 independently contribute to NE structure and its integrity through distinct lipid metabolic pathways, highlighting their complementary roles in nuclear membrane homeostasis. This study represents a significant step forward in the field of NE biology to unravel the complexities of nuclear membrane dynamics.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA