The pH signaling transcription factor PacC mediates the growth of Trichophyton rubrum on human nail in vitro.

We report here the isolation, molecular cloning and initial characterization of the Trichophytonrubrum pacC gene, which encodes a putative protein that is homologous to the PacC/Rim101p family of pH signaling transcription regulators. The promoter region of the T. rubrumpacC gene contains four recognition sites 5'-GCCAAG-3' for the PacC protein, suggesting that the transcription of this gene itself could be induced under alkaline growth conditions. The enhanced expression profile of the T. rubrumpacC gene in an alkaline environment was confirmed by Northern blotting analysis. We also report that the disruption of pacC gene decreased both the secretion of keratinolytic proteases and the ability of the mutant pacC-1 to grow on human nail fragments as the sole source of nutrition, i.e., growth of the dermatophyte T. rubrum appear to be related to molecular events which depend on the action of protein PacC.