Functional Analysis Of Candida Albicans Gene CaFSP1 And The Disruption Of CaMCI4

In this study, we have cloned the Candida albicans CaFSP1 gene, which encodes a protein of 411 amino acids. The protein encoded by CaFSP1 shares 57% identity and 73% similarity with the protein encoded by its Sacchromycease cerevisae homolog ScYMR034c. We constructed the homozygous mutant for CaFSP1 with the traditional URA3 knockout cassette, and its genotype had been confirmed by PCR and Southern blot analysis. The homozygous mutant for CaFSP1 showed sensitivity to SDS, NaCl, CaCl2 and KCl, tolerance to LiCl, H2O2 and ZnCl2,as well as resistance to the antifungal drugs fluconazole and terbinafine. In addition, deletion of CaFSP1 promoted the growth of hyphae of C. albicans, limited the invasive outgrowth in Spider medium, as well as changed the surface morphology of coloneys. Reintroduction of CaFSP1 gene back to the homozygous mutant recovered the phenotypes above. We speculate that CaFSP1 gene is related with the metabolism of sterols and sphingolipids in C. albicans, both of which are very important for nomal function of cell membrane and morphologous switch. Deletion of ScYMR034c also casued yeast cells sensitive to NaCl and KCl but not to other ions and antifungal drugs. The CaFSP1 gene did not complement the defects of the deletion mutant for ScYMR034c. Yeast mutant acr3â–³/ acr3â–³showed sensitivity to the fluconazole, however, further deletion of ScACR3 gene in the yeast ymr034 mutant did not cause yeast cells being sensitive to the fluconazole. With the same strategy, we also have deleted the two alleles of MCI4 gene in C. albicans, which codes for NADH dehydrogenase, for further study of its function as important electron transport carrier in mitochondria .