CHARACTERIZATION AND PARTIAL NUCLEOTIDE-SEQUENCE OF THE DNA FINGERPRINTING PROBE CA3 OF CANDIDA-ALBICANS

The moderately repetitive Ca3 fragment of Candida albicans has been us ed as an effective DNA fingerprinting probe in epidemiological studies . EcoRI digestion of Ca3 DNA results in seven fragments of 4.2 kb (A), 2.98 kb (B), 2.85 kb (C), 0.77 kb (D1), 0.77 kb (D2), 0.38 kb (E), an d 0.30 kb (F). Five of these EcoRI fragments have been mapped in the 5 '-3' order C B D1 A D2. The intact Ca3 probe and the three largest Eco RI fragments, A, B, and C, were individually used to probe Southern bl ots of EcoRI-digested DNA of a set of test strains, transverse alterna ting field electrophoresis-separated chromosomes of strain 3153A, and Northern (RNA) blots of test strain 3153A. Fragments A, B, and C each generate a different Southern blot hybridization pattern with EcoRI-di gested whole-cell DNA; Ca3 sequences are present in at least five of s even separable chromosomes and a minichromosome of strain 3153A; fragm ents A, B, and C are distributed differently on chromosomes; and fragm ents A, B, and C do not cross-hybridize. Ca3 hybridizes to three major transcripts of 2.8, 2.3, and 1.5 kb. Fragment A hybridizes intensely to the 1.5-kb transcript, while fragments B and C both hybridize inten sely to the 2.8- and 2.3-kb transcripts. The B fragment, which contain s 2,980 bp and contributes to the major portion of the Ca3 pattern, wa s sequenced. Both direct and inverted repeat sequence motifs were iden tified. These results provide us with initial insights into the evolut ion of the Ca3 pattern and the nature of the probe.