CDNA cloning of Candida albicans aspartic proteinase and its diagnostic application

Abstract

The expanding of immunocompromised individuals has focused attention on the importance of Candida species as an opportunistic fungal pathogen. C. albicans is a major infectious fungal agent in humans, invading by attachment to the host cells via cell-surface adhesive molecules. Once attached, C. albicans cells proliferate and release extracellular aspartic proteinase, which aids them to invade the integument of the host. Few extracellular enzymes have been described as virulence factors, but only extracellular an aspartic acid proteinase has received intense attention. There seems to be a relationship between the production of aspartic proteinase by C. albicans and its virulence (7, 9, 13), but the actual role of proteinase as the virulence factor remains unclear. Yamamoto et al. (20) reported that all strains of C. albicans tested secrete proteinase extracellularly, and they sequenced the first 23 amino acids of the N-terminal of the proteinase from their C. albicans No. 114. We have undertaken the cDNA cloning of this enzyme using the polymerase chain reaction (PCR) with mixed primers constructed from the information published by that group. This enzyme has very recently sequenced from the C. albicans strain ATCC10231 (6). We also show the results of comparison of our sequence with theirs and other related enzymes.