Transcript profiling of a MAP kinase pathway in C. albicans

In C. albicans, a MAP kinase pathway has been implicated in aspects of controlling hyphal development. We have examined the transcription profile of cells deleted for the transcription factor Cph1 as well as Cst20, Hst7 and Cek1, three upstream kinases potentially involved in Cph1 regulation. Deletion of these four elements does not block filament induction by serum and does not dramatically affect the transcription profile of yeast-hyphal transition, but deletion of CPH1 delays filamentation. Over-expression of Cph1 by ADH1pt-CPH1 significantly enhances filamentation, suggesting that Cph1 is helpful but not essential for filament induction. Interestingly, the transcription profile of ADH1pt-CPH1 expressing cells under yeast conditions is similar to that of wild type strains undergoing the yeast-hyphal transition. Finally, it appears that Cek1 and its regulators Hst7 and Cst20 may control the repression of genes such as CHT2 through a process independent of the Cph1p transcription factor