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Evolución de un complejo MCM en las moscas que promueve cruces meioticos al bloquear la helicasa BLM
Kathryn P Kohl1, Corbin D Jones, Jeff Sekelsky
1Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Science (New York, N.Y.)
|December 11, 2012
Resumen
En las moscas, las proteínas de mantenimiento del minicromosoma (MCM) reemplazaron el complejo Msh4-Msh5 para garantizar la generación de cruce meiotico. Este complejo MCM evolucionó para facilitar los cruces, superando la pérdida de Msh4-Msh5.5.
Área de la Ciencia:
- Genética La genética.
- Biología Molecular Biología Molecular
- Biología evolutiva Biología evolutiva.
Sus antecedentes:
- La formación de cruce meiótico en eucariotas a menudo implica el heterodímero Msh4-Msh5 que inhibe las anti-crossover helicasas.
- Las proteínas Msh4 y Msh5 están ausentes en moscas como Drosophila y Glossina.
Objetivo del estudio:
- Identificar las proteínas que reemplazan funcionalmente el heterodimero Msh4-Msh5 en Drosophila para la generación de cruce meiotico.
- Para investigar el origen evolutivo y la función de estas proteínas de reemplazo.
Principales métodos:
- Análisis genético de mutantes de Drosophila para los genes clave (rec, mei-217, mei-218).
- Estudios de interacción bioquímica para identificar complejos de proteínas.
- Genómica comparativa para rastrear la historia evolutiva de las proteínas MCM.
Principales resultados:
- Se identificó un complejo de proteínas de mantenimiento de minicromosomas (MCM), incluyendo REC (MCM8 ortholog) y las nuevas proteínas MEI-217/MEI-218.
- El REC evolucionó bajo selección positiva en moscas e interactúa con MEI-217/MEI-218, una proteína MCM específica de metazoos.
- Las mutaciones en rec, mei-217 o mei-218 redujeron los cruces meióticos, pero esto fue rescatado mediante la eliminación de la helicasa del síndrome de Bloom (BLM) ortholog.
Conclusiones:
- Las proteínas de mantenimiento de minicromosomas (MCM) fueron reutilizados para formar un nuevo complejo que sustituye a la función pro-crossover meiotic de Msh4-Msh5 en las moscas.
- Este complejo MCM juega un papel crucial en la regulación de los cruces meioticos en ausencia de Msh4-Msh5.
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