1887

Abstract

The ALS (gglutinin-ike equence) gene family of encodes eight cell-surface glycoproteins, some of which are involved in adherence to host surfaces. A mutational analysis of each ALS gene is currently being performed to deduce the functions of the encoded proteins and to better understand the role of these proteins in biology and pathogenesis. This paper describes construction of an / mutant and comparison of its phenotype to an / strain. Efforts to disrupt indicated that the gene could be deleted in two transformation steps, suggesting that the gene is encoded by a single locus and that the -like locus, , does not exist. Strains lacking or did not exhibit a defect in germ tube formation when grown in RPMI 1640 medium, but the / mutant formed significantly fewer germ tubes in Lee medium. Analysis of and promoter activity using green fluorescent protein (GFP) reporter strains and flow cytometry showed that when cells are placed into medium that promotes germ tube formation, is transcribed prior to . Comparison of the mutant strains in adhesion assays showed that the / strain was defective in adhesion to both human umbilical vein endothelial cells (HUVEC) and buccal epithelial cells (BEC), but not to fibronectin-coated plastic plates. In contrast, the / strain showed decreased adherence to HUVEC, but adherence to BEC and fibronectin were the same as wild-type controls. Inoculation of the buccal reconstituted human epithelium (RHE) model of oral candidiasis with the mutant strains showed nearly a total lack of adhesion and epithelial destruction by the / mutant while the / strain showed only a slightly reduced degree of epithelial destruction compared to the wild-type control. Adhesion data presented here suggest that, in the assays performed, loss of Als3p affects adhesion more than loss of Als1p. Collectively, these results demonstrate functional similarities and differences between Als1p and Als3p, and suggest the potential for more complex interrelationships between the ALS genes and their encoded proteins.

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2004-07-01
2024-03-28
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