Structural analysis of a Candida glabrata centromere and its functional homology to the Saccharomyces cerevisiae centromere.

Abstract

A 451-bp fragment exhibiting centromere activity had been previously isolated from Candida glabrata genomic DNA. It contains three elements, CgCDEI, CgCDEII and CgCDEIII, highly homologous to those of Saccharomyces cerevisiae. In this study, the requirement of each element for centromere function was analyzed in detail. Deletion analysis identified a small fragment of 153 bp, which included all three elements, to be sufficient for centromere activity. Linker substitution analysis of CgCDEI and CgCDEIII revealed that both elements are required for centromere function. Some of the substitution mutations in CgCDEIII caused a complete loss of centromere activity. These results suggested a functional similarity of centromeres between C. glabrata and S. cerevisiae. However, the C. glabrata centromere did not function in S. cerevisiae cells, suggesting species specificity of the C. glabrata centromere. To examine whether species specificity of the centromeres between these two yeasts does exist, chimeric centromeres between the two species were constructed. Exchange of CgCDEII or CgCDEIII with CDEII or CDEIII of S. cerevisiae, respectively, increased C. glabrata centromere activity in S. cerevisiae, indicating participation of the two elements in determining the species specificity of centromere function.