Sapporo Medical Journal

Abstract : The morphogenetic switch from yeast to hyphae form under the regulation of transcription regulatory genes in response to the host environment is the major contributor to the pathogenesis of C. albicans. Tec1p of C. albicans, a transcription factor belonging to the TEA transcription factor family, harbors a conserved TEA domain for DNA binding in the N-terminal of the transcription proteins. Tec1p is involved in mediating morphological change by activating different signaling pathways that lead to hyphal formation. The knockout strain tec1/tec1 is not capable of hyphae development in vitro and is avirulent in vivo. To shed the light on the relationships between the structure and function of the C. albicans Tec1p protein, we examined several mutant TEC1 strains for biofilm formation and growth rate. The TEC1 recombination cassette was constructed by fusing the TEC1 ORFs behind a tetracycline promoter. The cassette is flanked with a homologous sequence of ADH1 promoter to facilitate homologous recombination into the promoter region of the ADH1 allele of the tec1/tec1 of the CaAs12 strain. The studies of biofilm formation and growth rate of TEC1 mutants have revealed an essential role of CHAM (C-terminal Hyphal Activation Motif) in exerting virulence in Candida albicans. Herewith we conclude that the activity of Tec1p cannot be executed by autonomous activation of Tec1p itself but rather by a heterodimeric complex formation with a cooperative partner which is not discovered unti