Up-regulation of two Candida albicans genes in the rat model of oral candidiasis detected by differential display.

Candida albicans is an opportunistic fungal pathogen responsible for the largest percentage of fungal-mediated oral and oesophageal disease. In this regard, knowledge concerning patterns of gene expression during the establishment and/or maintenance of infection may be the key to the design of new strategies for treatment, as well as providing insight into pathogenesis. To address this issue, experiments were performed that utilized differential display to compare the spectrum of C. albicans genes expressed during oral infection versus growth in in vitroculture. Experimentally, the rat model of oral candidiasis served as the in vivo source. After initiation of infection and subsequent harvesting of C. albicans from the rat oral cavity, RNA was isolated, and used with a small number of primers in reverse-transcriptase polymerase chain reaction (RT-PCR) and differential display experiments. Fragments unique to in vivo samples were subcloned and sequenced. Southern blot analysis verified the origin of seven fragments as fromC. albicans. Additionally, specific RT-PCR confirmed that two of these fragments represented genes that were up-regulated during C. albicans in vivo growth in the rat model. Database searches indicated the fragments share homology with a member of the C. albicans agglutinin gene family and to a bacterial gene (gidB) possibly involved in cell division.