Temporal and Functional Relationship between Synaptonemal Complex Morphogenesis and Recombination during Meiosis.

During prophase of meiosis I, programmed double strand breaks (DSBs) are processed into crossovers, a critical requirement for segregation of homologous chromosomes (homologs) and genome haploidization in sexually reproducing organisms. Crossovers form via homologous recombination in close temporospatial association with morphogenesis of the synaptonemal complex (SC), a proteinaceous structure that connects paired homologs along their length during the pachytene stage. Synapsis and recombination are a paradigm for the interplay between higher order chromosome structure and DNA metabolism, yet their temporal and functional relationship remains poorly understood.

Histone deacetylation primes self-propagation of heterochromatin domains to promote epigenetic inheritance.

Heterochromatin assembly, involving histone H3 lysine-9 methylation (H3K9me), is nucleated at specific genomic sites but can self-propagate across extended domains and, indeed, generations. Self-propagation requires Clr4/Suv39h methyltransferase recruitment by pre-existing H3K9 tri-methylation (H3K9me3) to perpetuate H3K9me deposition and is dramatically affected by chromatin context. However, the mechanism priming self-propagation of heterochromatin remains undefined.

The SR-protein Npl3 is an essential component of the meiotic splicing regulatory network in Saccharomyces cerevisiae.

The meiotic gene expression program in Saccharomyces cerevisiae involves regulated splicing of meiosis-specific genes via multiple splicing activators (e.g. Mer1, Nam8, Tgs1).

DNA Helicase Mph1 Ensures Meiotic Recombination between Parental Chromosomes by Dissociating Precocious Displacement Loops.

Meiotic pairing between parental chromosomes (homologs) is required for formation of haploid gametes. Homolog pairing depends on recombination initiation via programmed double-strand breaks (DSBs). Although DSBs appear prior to pairing, the homolog, rather than the sister chromatid, is used as repair partner for crossing over.

A nuclear role for the DEAD-box protein Dbp5 in tRNA export.

Dbp5 is an essential DEAD-box protein that mediates nuclear mRNP export. Dbp5 also shuttles between nuclear and cytoplasmic compartments with reported roles in transcription, ribosomal subunit export, and translation; however, the mechanism(s) by which nucleocytoplasmic transport occurs and how Dbp5 specifically contributes to each of these processes remains unclear. Towards understanding the functions and transport of Dbp5 in , alanine scanning mutagenesis was used to generate point mutants at all possible residues within a GFP-Dbp5 reporter.

Stopping chromosomes from breaking bad.

The scaffolding that holds chromosome pairs together plays a key role in limiting the levels of double-strand breaks.

Control of meiotic pairing and recombination by chromosomally tethered 26S proteasome.

During meiosis, paired homologous chromosomes (homologs) become linked via the synaptonemal complex (SC) and crossovers. Crossovers mediate homolog segregation and arise from self-inflicted double-strand breaks (DSBs). Here, we identified a role for the proteasome, the multisubunit protease that degrades proteins in the nucleus and cytoplasm, in homolog juxtaposition and crossing over.

Correction: Mek1 Down Regulates Rad51 Activity during Yeast Meiosis by Phosphorylation of Hed1.

[This corrects the article DOI: 10.1371/journal.pgen.

Mek1 Down Regulates Rad51 Activity during Yeast Meiosis by Phosphorylation of Hed1.

During meiosis, programmed double strand breaks (DSBs) are repaired preferentially between homologs to generate crossovers that promote proper chromosome segregation at Meiosis I. In many organisms, there are two strand exchange proteins, Rad51 and the meiosis-specific Dmc1, required for interhomolog (IH) bias. This bias requires the presence, but not the strand exchange activity of Rad51, while Dmc1 is responsible for the bulk of meiotic recombination.

Phosphorylation of the Synaptonemal Complex Protein Zip1 Regulates the Crossover/Noncrossover Decision during Yeast Meiosis.

Interhomolog crossovers promote proper chromosome segregation during meiosis and are formed by the regulated repair of programmed double-strand breaks. This regulation requires components of the synaptonemal complex (SC), a proteinaceous structure formed between homologous chromosomes. In yeast, SC formation requires the "ZMM" genes, which encode a functionally diverse set of proteins, including the transverse filament protein, Zip1.