Candida albicans is the most frequently isolated human fungal pathogen and is an important agent of hospital acquired infections. To determine if a gene encodes a protein that contributes to its ability to cause disease, both alleles of a gene are typically disrupted. Historically, gene disruption in C. albicans utilizes the URA3 gene as a selectable marker in a URA3 auxotrophic strain. It was discovered that some of the mutant strains created using the “URA-blaster” technique had reduced levels of URA3 expression that affected the phenotypes of the mutant strains. Previously, we created a mutant strain of Candida albicans in which the MBP1 gene has been disrupted using the “URA-blaster” technique. To determine if the mutant phenotype observed is due to the disruption of the MBP1 gene or is an artifact due to reduced levels of URA3 expression, we are assessing URA3 gene functionality by assaying for OMP decarboxylase activity using protein lysates from wild-type and MBP1 mutant strains. Currently, we are making protein lysates which will be assessed for URA3 activity. Once we obtain the results of this experiment it will help to clarify the significance of the phenotypes observed in the MBP1 null mutant strains.
