Abstract
Meiosis requires that each chromosome find its homologous partner and undergo at least one crossover. X-Y chromosome segregation hinges on efficient crossing-over in a very small region of homology, the pseudoautosomal region (PAR). We find that mouse PAR DNA occupies unusually long chromosome axes, potentially as shorter chromatin loops, predicted to promote double-strand break (DSB) formation. Most PARs show delayed appearance of RAD51/DMC1 foci, which mark DSB ends, and all PARs undergo delayed DSB-mediated homologous pairing. Analysis of Spo11β isoform-specific transgenic mice revealed that late RAD51/DMC1 foci in the PAR are genetically distinct from both early PAR foci and global foci and that late PAR foci promote efficient X-Y pairing, recombination, and male fertility. Our findings uncover specific mechanisms that surmount the unique challenges of X-Y recombination.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Cell Cycle Proteins / metabolism
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Chromatin / chemistry
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Chromatin / metabolism
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Chromosome Pairing*
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Chromosome Segregation
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Crossing Over, Genetic*
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DNA Breaks, Double-Stranded
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Endodeoxyribonucleases / genetics
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Endodeoxyribonucleases / metabolism*
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Female
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In Situ Hybridization, Fluorescence
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Male
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Meiosis*
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Mice
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Mice, Inbred C57BL
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Mice, Transgenic
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Molecular Sequence Data
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Nuclear Proteins / metabolism
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Phosphate-Binding Proteins
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Protein Isoforms
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Rad51 Recombinase / metabolism
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X Chromosome / physiology*
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Y Chromosome / physiology*
Substances
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Cell Cycle Proteins
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Chromatin
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Dmc1 protein, mouse
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Nuclear Proteins
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Phosphate-Binding Proteins
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Protein Isoforms
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Rad51 Recombinase
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Rad51 protein, mouse
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Endodeoxyribonucleases
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meiotic recombination protein SPO11