High impact information on MSH4

• Immunofluorescence experiments demonstrate that the Msh4 protein is localized to discrete sites on pachytene chromosomes [1].
• RNAi-induced down-regulation of the MSH4 gene resulted in a similar fertility and meiotic phenotype [2].
• Msh5 mutants are phenotypically similar to mutants in the meiosis-specific gene MSH4 (Ross-Macdonald and Roeder 1994) [3].
• Double mutant analysis using msh4 msh5 diploids demonstrates that the two genes are in the same epistasis group and therefore are likely to function in a similar process--namely, the facilitation of interhomolog crossovers during meiosis [3].
• With respect to the defect in interference and the level of crossing over, msh4 is similar to the zip1 mutant, which lacks a structural component of the synaptonemal complex (SC) [4].

Biological context of MSH4

• MSH2, 3, and 6 function in mismatch repair in both vegetative and meiotic cells, whereas MSH4 and MSH5 act specifically to facilitate crossovers between homologs during meiosis [5].
• EXO1 and MSH4 differentially affect crossing-over and segregation [6].
• In the msh4 mutant, SC formation is delayed compared to wild type, and full synapsis is achieved in only about half of all nuclei [4].
• Msh4 is not required for meiotic mismatch repair or gene conversion, but it is required for wild-type levels of crossing over [4].

Co-localisations of MSH4

• The Msh4 protein localizes to discrete foci on meiotic chromosomes and colocalizes with Zip2, a protein involved in the initiation of chromosome synapsis [4].

Other interactions of MSH4

• The simultaneous defects in synapsis and interference observed in msh4 (and also zip1 and ndj1/tam1) suggest a role for the SC in mediating interference [4].
• The 5'-3' exonuclease Exo1p from Saccharomyces cerevisiae is required for wild-type levels of meiotic crossing-over and normal meiotic chromosome segregation as is the meiosis-specific MutS homologue, Msh4p [6].
• In yeast, MSH4, a meiosis-specific homologue of the bacterial MutS protein, is required for meiotic recombination [7].

References