The basic helix-loop-helix transcription factor Cph2 regulates hyphal development in Candida albicans partly via TEC1

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Candida albicans exhibits a yeast-to-hypha transition critical for its virulence.
• This morphogenetic switch is regulated by complex signaling pathways, including MAPK and PKA pathways.
• Understanding novel regulators is key to deciphering fungal development.

Purpose of the Study:

• To identify and characterize novel transcription factors involved in Candida albicans hyphal development.
• To elucidate the regulatory mechanisms underlying the yeast-to-hypha transition.
• To investigate the role of the identified transcription factor Cph2 in hyphal gene regulation.

Main Methods:

• Identification of Cph2 through functional screening in Saccharomyces cerevisiae.
• Analysis of cph2 mutant strains in Candida albicans under various growth conditions.
• Northern blot analysis to assess gene expression.
• In vitro gel mobility shift assays to determine DNA binding.
• Gene expression analysis to evaluate the role of Cph2 in Tec1 regulation.

Main Results:

• Cph2, a Myc-subfamily basic helix-loop-helix transcription factor, promotes pseudohyphal growth.
• cph2 mutant strains show defects in hyphal development and hypha-specific gene induction.
• Cph2 directly binds to regulatory elements upstream of TEC1, inducing its transcription.
• Ectopic TEC1 expression rescues the hyphal defect in cph2 mutants.
• Cph2's function in hyphal development is mediated through Tec1 and is independent of Cph1 and Efg1 pathways.

Conclusions:

• Cph2 is a novel regulator of hyphal development in Candida albicans.
• Cph2 functions upstream of Tec1, mediating hyphal gene transcription.
• The Cph2-Tec1 pathway represents a distinct regulatory mechanism for hyphal morphogenesis in C. albicans.