DYNAMIC EXPRESSION OF CELL-WALL PROTEINS OF CANDIDA-ALBICANS REVEALEDBY PROBES FROM CDNA CLONES

Five cDNA clones were selected from the positive clones detected by sc reening a germ tube expression library constructed in lambda gt11 with rabbit antisera raised against cell wall extracts of Candida albicans . The selected clones were amplified and used to obtain affinity purif ied antibodies by eluting from the expressed proteins that had been pr eviously transferred onto nitrocellulose discs. The antibodies obtaine d were used as probes in immunoblots of the cell wall extracts separat ed by denaturing polyacrylamide electrophoresis. A single protein band was detected for each clone. Detection of products of the cloned sequ ences varied according to the extraction procedure and/or cell morphol ogy. These products included bands exhibiting apparent molecular weigh ts of 40, 58, 68 and 70 kDa present in beta-mercaptoethanol (beta ME) extracts from both yeast and germ tubes, and a 30 kDa beta ME extracte d protein specific for germ tubes. The expression of these products at the cell surface was confirmed by indirect immunofluorescence. Expres sion of the mRNAs of the different cDNA clones varied according to gro wth- and morphology-related factors and showed no direct correlation b etween expression and presence in the cell wall. These observations su ggest that complex mechanisms are involved in the regulation and expre ssion of cell surface components of C. albicans.