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Sci Rep. 2017 May 3;7(1):1393. doi: 10.1038/s41598-017-00742-3.

Functional organization of protein determinants of meiotic DNA break hotspots.

Author information

1
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA.
2
Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA, 94143, USA.
3
Instituto de Biología Funcional y Genómica, CSIC/University of Salamanca, C/Zacarías González 2, 37007, Salamanca, Spain.
4
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA. gsmith@fhcrc.org.

Abstract

During Schizosaccharomyces pombe meiotic prophase, homologous chromosomes are co-aligned by linear elements (LinEs) analogous to the axial elements of the synaptonemal complex (SC) in other organisms. LinE proteins also promote the formation of meiotic DNA double-strand breaks (DSBs), the precursors of cross-overs. Rec10 is required for essentially all DSBs and recombination, and three others (Rec25, Rec27, and Mug20) are protein determinants of DSB hotspots - they bind DSB hotspots with high specificity and are required for DSB formation there. These four LinE proteins co-localize in the nucleus in an interdependent way, suggesting they form a complex. We used random mutagenesis to uncover recombination-deficient missense mutants with novel properties. Some missense mutations changed essential residues conserved among Schizosaccharomyces species. DSB formation, gene conversion, and crossing-over were coordinately reduced in the mutants tested. Based on our mutant analysis, we revised the rec27 open reading frame: the new start codon is in the previously annotated first intron. Genetic and fluorescence-microscopy assays indicated that the Rec10 N- and C-terminal regions have complex interactions with Rec25. These mutants are a valuable resource to elucidate further how LinE proteins and the related SCs of other species regulate meiotic DSB formation to form crossovers crucial for meiosis.

PMID:
28469148
PMCID:
PMC5431104
DOI:
10.1038/s41598-017-00742-3
[Indexed for MEDLINE]
Free PMC Article

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