Project description:Successful meiotic recombination, and thus fertility, depends on conserved axis proteins that organize chromosomes into arrays of anchored chromatin loops and provide a protected environment for DNA exchange. Here, we show that the stereotypic chromosomal distribution of axis proteins in S. cerevisiae is the additive result of two independent pathways: a cohesin-dependent pathway, which was previously identified and mediates focal enrichment of axis proteins at gene ends, and a parallel cohesin-independent pathway that recruits axis proteins to broad genomic islands with high gene density. These islands exhibit elevated markers of crossover recombination as well as increased nucleosome density, which we show is a direct consequence of the underlying DNA sequence. A predicted PHD domain in the center of the axis factor Hop1 specifically mediates cohesin-independent axis recruitment. Intriguingly, other chromosome organizers, including cohesin, condensin, and topoisomerases, are differentially depleted from the same regions even in non-meiotic cells, indicating that these DNA sequence-defined chromatin islands exert a general influence on the patterning of chromosome structure.

2022-04-08 | GSE156040 | GEO

Proximity labeling reveals new functional relationships between meiotic recombination proteins in S. cerevisiae

Project description:Several protein ensembles facilitate meiotic crossover recombination and the associated process of synaptonemal complex (SC) assembly during meiosis. We have employed proximity labeling as a phenotyping tool to investigate functional requirements for spatial relationships between meiotic recombination and SC proteins in S. cerevisiae, and to gain deeper insight into the molecular deficits of crossover-deficient meiotic mutants. We find that recombination initiation and synaptonemal complex structures are dispensable for proximity labeling of the Zip3 E3 ligase by components of the ZZS ensemble (Zip2, Zip4 and Spo16) but enzymes associated with early steps in recombination are required for Zip3 proximity labeling by MutSg, consistent with the possibility that MutSg joins Zip3 only after a specific recombination intermediate has been generated. Proximity labeling furthermore suggests that a key defect of crossover-defective, SC-proficient zip1 separation-of-function mutants is a failure to assemble an early recombination ensemble where MutSg can properly engage Zip3. We also find that the SC structural protein Ecm11 is proximity labeled by ZZS proteins in a Zip4-dependent and Zip1-independent manner, but by Zip3 and Msh4 at least in part via a distinct pathway that relies on Zip1. Finally, streptavidin pulldown followed by mass spectrometry on eleven proximity labeling strains uncovered shared proximity targets of SC and crossover-associated proteins, some of which have not yet been implicated in meiotic recombination or SC formation highlighting the potential of proximity labeling as a discovery tool.

2024-10-02 | PXD053621 | Pride

Functional impact of the H2A.Z histone variant during meiosis in Saccharomyces cerevisiae

Project description:Among the collection of chromatin modifications that influence its function and structure, the substitution of canonical histones by the so-called histone variants is one of the most prominent actions. Since crucial meiotic transactions are modulated by chromatin, here we investigate the functional contribution of the H2A.Z histone variant during both unperturbed meiosis and upon challenging conditions where the meiotic recombination checkpoint is triggered in budding yeast by the absence of the synaptonemal complex component Zip1. We have found that H2A.Z localizes to meiotic chromosomes in an SWR1-dependent manner. Although meiotic recombination is not substantially altered, the htz1 mutant (lacking H2A.Z) shows slower meiotic progression, impaired sporulation and reduced spore viability. These phenotypes are likely accounted for by the misregulation of meiotic gene expression landscape observed in htz1. In the zip1 mutant, the absence of H2A.Z results in a tighter meiotic arrest imposed by the meiotic recombination checkpoint. We have found that Mec1-dependent Hop1-T318 phosphorylation and the ensuing Mek1 activation are not significantly altered in zip1 htz1; however, downstream checkpoint targets, such as the meiosis I-promoting factors Ndt80, Cdc5 and Clb1, are drastically down-regulated. The study of the checkpoint response in zip1 htz1 has also allowed us to reveal the existence of an additional function of the Swe1 kinase, independent of CDK inhibitory phosphorylation, which is relevant to restrain meiotic cell cycle progression. In summary, our study shows that the H2A.Z histone variant impacts various aspects of meiotic development adding further insight into the relevance of chromatin dynamics for accurate gametogenesis.

2018-02-02 | GSE110022 | GEO

Saccharomyces cerevisiae

Project description:Global Analysis of Yeast mRNPs

| PRJNA197348 | ENA

Meiotic crossover landscape within RAC1 disease resistance gene

Project description:Meiotic crossover landscape within RAC1 disease resistance gene

| PRJEB24064 | ENA

Yeast (Saccharomyces cerevisiae) synchronized meiotic timecourse II

Project description:transcriptional profiling of yeast meiotic culture

2016-11-18 | GSE90006 | GEO

Yeast (Saccharomyces cerevisiae) synchronized meiotic timecourse I

Project description:transcriptional profiling of yeast meiotic culture