Evolution of a MCM complex in flies promoting meiotic crossovers by blocking BLM helicase
Generation of meiotic crossovers in many eukaryotes requires the elimination of anti-crossover activities by utilizing the Msh4–Msh5 heterodimer to block helicases. Msh4 and Msh5 have been lost from the flies Drosophila and Glossina but we identified a complex of mini-chromosome maintenance (MCM) pr...
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Published in | Science (American Association for the Advancement of Science) Vol. 338; no. 6112; pp. 1363 - 1365 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
07.12.2012
|
Online Access | Get full text |
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Summary: | Generation of meiotic crossovers in many eukaryotes requires the elimination of anti-crossover activities by utilizing the Msh4–Msh5 heterodimer to block helicases. Msh4 and Msh5 have been lost from the flies
Drosophila
and
Glossina
but we identified a complex of mini-chromosome maintenance (MCM) proteins that functionally replace Msh4–Msh5. REC, an ortholog of MCM8 that evolved under strong positive selection in flies, interacts with MEI-217 and MEI-218, which arose from a previously undescribed metazoan-specific MCM protein. Meiotic crossovers are reduced in
Drosophila rec
,
mei-217
, and
mei-218
mutants; however, removal of the Bloom syndrome helicase ortholog restores crossovers. Thus, MCMs were co-opted into a novel complex that replaces the meiotic pro-crossover function of Msh4–Msh5 in flies. |
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ISSN: | 0036-8075 1095-9203 |
DOI: | 10.1126/science.1228190 |