CLONING OF THE CHITIN SYNTHASE-3 GENE FROM CANDIDA-ALBICANS AND ITS EXPRESSION DURING YEAST-HYPHAL TRANSITION

The chitin synthase 3 gene (CACHS3) has been cloned from Candida albic ans. The yeast CAL1 gene encoding the chitin synthase 3 of Saccharomyc es cerevisiae was used as a probe for the isolation of the gene from C . albicans. The CAL1 homolog was identified in Southern blots of C. al bicans genomic DNA and cloned from a C. albicans genomic DNA library. The nucleotide sequences of two partial clones were determined and com bined giving a total length of 4610 bp. A continuous open reading fram e of 3525 bp encoding a predicted protein of 1175 amino acids and mole cular mass of 131 850 daltons was identified. A comparison of the dedu ced amino acid sequences of CAL1 and the Candida chitin synthase 3 pro tein showed 59.3% identitiy. Southern blot analysis indicates that the CACHS3 gene is present in a single copy in the genome and maps to chr omosome 1. Northern blot analysis shows that expression of chitin synt hase 3 gene is dramatically increased during the transition from the y east to the hyphal form of C. albicans. This change in transcription l evel strongly suggests that CACHS3 may play a role in Candida morphoge nesis.