科研之友
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摘要
rad52-Delta Delta and, to a lesser extent, rad51-Delta Delta deletants of Candida albicans displayed slow growth and aberrant filamentous morphology whereas rad59-Delta Delta mutants, both by growth rate and morphology resembled wild type. In this study, we have constructed pair-wise double deletants to analyze genetic interactions among these homologous recombination (HR) proteins that affect growth and morphology traits. When grown in liquid YPD medium, double mutant rad51-Delta Delta rad59-Delta Delta exhibited growth rates, cell and colony morphologies, and plating efficiencies that were not significantly different from those observed for rad51-Delta Delta. The same was true for rad52-Delta Delta rad59-Delta Delta compared to rad52-Delta Delta. Slow growth and decreased plating efficiency were caused, at least in part, by a decreased viability, as deduced from FUN1 staining. Flow cytometry and microscopic studies of filamentous mutant populations revealed major changes in cell ploidy, size and morphology, whereas DAPI staining identified complex nuclear rearrangements in yeast and filamentous cells. These phenotypes were not observed in the rad59-Delta Delta mutant populations. Our results show that abolishing Rad51 functions induces the appearance of a subpopulation of aberrant yeast and filamentous forms with increased cell size and ploidy. The size of this complex subpopulation was exacerbated in rad52-Delta Delta mutants. The combination of filamentous cell morphology and viability phenotypes was reflected on the colony morphology of the respective mutants. We conclude that the rad52 mutation is epistatic to rad51 for all the morphological traits analyzed. We discuss these results in the light of the several functions of these recombination genes.
- 出版日期2015-1
