Dataset Information

Meiotic cohesin SMC1? provides prophase I centromeric cohesion and is required for multiple synapsis-associated functions.

ABSTRACT: Cohesin subunit SMC1? is specific and essential for meiosis. Previous studies showed functions of SMC1? in determining the axis-loop structure of synaptonemal complexes (SCs), in providing sister chromatid cohesion (SCC) in metaphase I and thereafter, in protecting telomere structure, and in synapsis. However, several central questions remained unanswered and concern roles of SMC1? in SCC and synapsis and processes related to these two processes. Here we show that SMC1? substantially supports prophase I SCC at centromeres but not along chromosome arms. Arm cohesion and some of centromeric cohesion in prophase I are provided by non-phosphorylated SMC1?. Besides supporting synapsis of autosomes, SMC1? is also required for synapsis and silencing of sex chromosomes. In absence of SMC1?, the silencing factor ?H2AX remains associated with asynapsed autosomes and fails to localize to sex chromosomes. Microarray expression studies revealed up-regulated sex chromosome genes and many down-regulated autosomal genes. SMC1? is further required for non-homologous chromosome associations observed in absence of SPO11 and thus of programmed double-strand breaks. These breaks are properly generated in Smc1??/? spermatocytes, but their repair is delayed on asynapsed chromosomes. SMC1? alone cannot support non-homologous associations. Together with previous knowledge, three main functions of SMC1? have emerged, which have multiple consequences for spermatocyte biology: generation of the loop-axis architecture of SCs, homologous and non-homologous synapsis, and SCC starting in early prophase I.

SUBMITTER: Biswas U

PROVIDER: S-EPMC3873225 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Meiotic cohesin SMC1β provides prophase I centromeric cohesion and is required for multiple synapsis-associated functions.

Biswas Uddipta U Wetzker Cornelia C Lange Julian J Christodoulou Eleni G EG Seifert Michael M Beyer Andreas A Jessberger Rolf R

PLoS genetics 20131226 12

Cohesin subunit SMC1β is specific and essential for meiosis. Previous studies showed functions of SMC1β in determining the axis-loop structure of synaptonemal complexes (SCs), in providing sister chromatid cohesion (SCC) in metaphase I and thereafter, in protecting telomere structure, and in synapsis. However, several central questions remained unanswered and concern roles of SMC1β in SCC and synapsis and processes related to these two processes. Here we show that SMC1β substantially supports pr ...[more]

PMID: 24385917

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Project description:Cohesion between sister chromatids is mediated by cohesin and is essential for proper meiotic segregation of both sister chromatids and homologs. solo encodes a Drosophila meiosis-specific cohesion protein with no apparent sequence homology to cohesins that is required in male meiosis for centromere cohesion, proper orientation of sister centromeres and centromere enrichment of the cohesin subunit SMC1. In this study, we show that solo is involved in multiple aspects of meiosis in female Drosophila. Null mutations in solo caused the following phenotypes: 1) high frequencies of homolog and sister chromatid nondisjunction (NDJ) and sharply reduced frequencies of homolog exchange; 2) reduced transmission of a ring-X chromosome, an indicator of elevated frequencies of sister chromatid exchange (SCE); 3) premature loss of centromere pairing and cohesion during prophase I, as indicated by elevated foci counts of the centromere protein CID; 4) instability of the lateral elements (LE)s and central regions of synaptonemal complexes (SCs), as indicated by fragmented and spotty staining of the chromosome core/LE component SMC1 and the transverse filament protein C(3)G, respectively, at all stages of pachytene. SOLO and SMC1 are both enriched on centromeres throughout prophase I, co-align along the lateral elements of SCs and reciprocally co-immunoprecipitate from ovarian protein extracts. Our studies demonstrate that SOLO is closely associated with meiotic cohesin and required both for enrichment of cohesin on centromeres and stable assembly of cohesin into chromosome cores. These events underlie and are required for stable cohesion of centromeres, synapsis of homologous chromosomes, and a recombination mechanism that suppresses SCE to preferentially generate homolog crossovers (homolog bias). We propose that SOLO is a subunit of a specialized meiotic cohesin complex that mediates both centromeric and axial arm cohesion and promotes homolog bias as a component of chromosome cores.

Dataset Information

Meiotic cohesin SMC1? provides prophase I centromeric cohesion and is required for multiple synapsis-associated functions.

Publications

Meiotic cohesin SMC1β provides prophase I centromeric cohesion and is required for multiple synapsis-associated functions.

Similar Datasets

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