Analysis of the chromosome rearrangement mechanism in the pathogenic yeast Candida albicans

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High frequency variation of phenotypes in the pathogenic yeast Candida albicans is presumed to be one of the virulence factors, and is related to the variation of the electrophoretic karyotypes by the pulsed field gel electrophoresis. The variation occurs due to rearrangements between the chromosomes, in which the repetitive sequences might be involved. Our aim of this study was to analyze the structure and function of the repeating sequences, RPSs, which we discoverd and characterized. In addition we studied the variation of electrophoretic karyotypes of freshly isolated Candida strains from various clinical specimens to examine possiblity of their application to epidemiological study.1. We cloned and sequenced the repeated sequences, RPSs, from individual chromosomes of C.albicans FC18, and characterized the diversity of their repeating structures which were due to short periodic repetitions of alt sequences. This feature was found to be similar to humanalpha-satellite DNA with its t … More andem repeat of ca.170 bp.2. RPSs were found to be localized in a limited region on every chromosomes except chromosome 4 of C.albicans FC18 as detemined by digestion with BamH1 and Xho1 and by hybridization with RPS.We constructed semi-macro physical map of the RPSs and their boundary regions on chromosome 6.3. The electrophoretic karyotypes of isolates taken from hospitalized patients were analyzed. No specific karyotypes was correlated with either the nature of the specimen or the hospital ward to which the patient had been admitted. Most isolates gave a pattern similar to that of FC18.4. The electrophoretic karyotypes of Candida strains isolated repeatedly from single patients during recurrent episodes of infections were almost identical with respect to each patient.5. We examined the strain relatedness of Candida albicans isolated from children with leukemia and their bedside parents using pulsed field gel electrophoresis, RFLP by SmaI digestion and the Southern hybridization of RFLPs by C.albicans-specific probe, RPS1. The results suggested that the transmission might have occurred between the patient and his (her) parents. Less