STRUCTURAL-ANALYSIS OF A CANDIDA-GLABRATA CENTROMERE AND ITS FUNCTIONAL HOMOLOGY TO THE SACCHAROMYCES-CEREVISIAE CENTROMERE

A 451-bp fragment exhibiting centromere activity had been previously i solated from Candida glabrata genomic DNA. It contains three elements, CgCDEI, CgCDEII and CgCDEIII, highly homologous to those of Saccharom yces cerevisiae. In this study, the requirement of each element for ce ntromere 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 Cg CDEI and CgCDEIII revealed that both elements are required for centrom ere function. Some of the substitution mutations in CgCDEIII caused a complete loss of centromere activity. These results suggested a functi onal 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. T o examine whether species specificity of the centromeres between these two yeasts does exist, chimeric centromeres between the two species w ere constructed. Exchange of CgCDEII or CgCDEIII with CDEII or CDEIII of S. cerevisiae, respectively, increased C. glabrata centromere activ ity in S. cerevisiae, indicating participation of the two elements in determining the species specificity of centromere function.