Two distinct surveillance mechanisms monitor meiotic chromosome metabolism in budding yeast.

Meiotic recombination is initiated by Spo11-generated DNA double-strand breaks (DSBs) . A fraction of total DSBs is processed into crossovers (CRs) between homologous chromosomes, which promote their accurate segregation at meiosis I (MI) . The coordination of recombination-associated events and MI progression is governed by the "pachytene checkpoint", which in ...
budding yeast requires Rad17, a component of a PCNA clamp-like complex, and Pch2, a putative AAA-ATPase . We show that two genetically separable pathways monitor the presence of distinct meiotic recombination-associated lesions: First, delayed MI progression in the presence of DNA repair intermediates is suppressed when RAD17 or SAE2, encoding a DSB-end processing factor , is deleted. Second, delayed MI progression in the presence of aberrant synaptonemal complex (SC) is suppressed when PCH2 is deleted. Importantly, ZIP1, encoding the central element of the SC , is required for PCH2-dependent checkpoint activation. Analysis of the rad17Deltapch2Delta double mutant revealed a redundant function regulating interhomolog CR formation. These findings suggest a link between the surveillance of distinct recombination-associated lesions, control of CR formation kinetics, and regulation of MI timing. A PCH2-ZIP1-dependent checkpoint in meiosis is likely conserved among synaptic organisms from yeast to human .
Mesh Terms:
Cell Cycle Proteins, Chromosomes, Fungal, Crossing Over, Genetic, DNA-Binding Proteins, Endonucleases, Meiosis, Nuclear Proteins, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Synaptonemal Complex
Curr. Biol.
Date: Dec. 19, 2006
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