Tid1/Rdh54 promotes colocalization of Rad51 and Dmc1 during meiotic recombination
| Autor: | Douglas K. Bishop, Akira Shinohara, Stephen L. Gasior, Miki Shinohara |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
Saccharomyces cerevisiae Proteins
DNA repair Mutant Guinea Pigs RAD51 Cell Cycle Proteins Saccharomyces cerevisiae Biology medicine.disease_cause Fungal Proteins Gene Expression Regulation Fungal medicine Animals Recombination Genetic Fungal protein Mutation Multidisciplinary fungi DNA Helicases Colocalization Biological Sciences Molecular biology DNA-Binding Proteins enzymes and coenzymes (carbohydrates) Meiosis DNA Repair Enzymes DMC1 Rad51 Recombinase Homologous recombination DNA Topoisomerases |
| Popis: | Two RecA homologs, Rad51 and Dmc1, assemble as cytologically visible complexes (foci) at the same sites on meiotic chromosomes. Time course analysis confirms that co-foci appear and disappear as the single predominant form. A large fraction of co-foci are eliminated in a red1 mutant, which is expected as a characteristic of the interhomolog-specific recombination pathway. Previous studies suggested that normal Dmc1 loading depends on Rad51. We show here that a mutation in TID1 / RDH54 , encoding a RAD54 homolog, reduces Rad51-Dmc1 colocalization relative to WT. A rad54 mutation, in contrast, has relatively little effect on RecA homolog foci except when strains also contain a tid1 / rdh54 mutation. The role of Tid1/Rdh54 in coordinating RecA homolog assembly may be very direct, because Tid1/Rdh54 is known to physically bind both Dmc1 and Rad51. Also, Dmc1 foci appear early in a tid1 / rdh54 mutant. Thus, Tid1 may normally act with Rad51 to promote ordered RecA homolog assembly by blocking Dmc1 until Rad51 is present. Finally, whereas double-staining foci predominate in WT nuclei, a subset of nuclei with expanded chromatin exhibit individual Rad51 and Dmc1 foci side-by-side, suggesting that a Rad51 homo-oligomer and a Dmc1 homo-oligomer assemble next to one another at the site of a single double-strand break (DSB) recombination intermediate. |
| Databáze: | OpenAIRE |
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