CLONING OF CDNAS CODING FOR CARDIDA ALBICANS CELL-SURFACE PROTEINS

Two cDNA libraries were constructed from mRNAs obtained from yeast cel ls and germ-tubes of Candida albicans in lambda gt11. Immunoscreening with polyclonal antibodies raised against cell wall components allowed the detection of 29 positive clones. Two of these clones were selecte d for their specific reactivity with antisera either from yeast (clone 11Y) or germ-tubes (clone 24M). cDNA fragments were isolated by the d igestion of lambda DNA With EcoRI. Southern blot analysis with these f ragments as probes demonstrated homology with C. albicans DNA, and by Northern analysis two mRNAs transcripts were detected with sizes of ap proximately 1.5 kb for 11Y and 1.1 kb for 24M. Both transcripts were p resent in yeast cells as well as in germ-tubes. The whole genes were i solated from a C. albicans genomic library in the YRp7 vector by hybri dization with the cDNA probes. Monospecific antibodies were purified f rom polyclonal antisera by affinity for the fusion proteins. Western b lot analysis with 11Y-specific antibodies revealed a cross-reactivity with material found in the yeast cell wall as well as in other subcell ular fractions, whereas clone 24M codes for a 30 kDa protein detected mainly in the membrane fraction and in the SDS-solubilized material fr om mycelial cell walls. Sequencing of the cDNA molecules and restricti on map of the cloned genes demonstrate that clone 11Y is an enolase pr eviously characterized in C. albicans, whereas clone 24M does not show significant homology with any other cloned gene.