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Target specificity of the Candida albicans Efg1 regulator
Author(s) -
Lassak Theresia,
Schneider Eva,
Bussmann Michael,
Kurtz Dagmar,
Manak J. Robert,
Srikantha Thyagarajan,
Soll David R.,
Ernst Joachim F.
Publication year - 2011
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2011.07837.x
Subject(s) - biology , promoter , candida albicans , regulator , gene isoform , gene , hypha , microbiology and biotechnology , genetics , gene expression
Summary Efg1 is a central transcriptional regulator of morphogenesis and metabolism in Candida albicans . In vivo genome‐wide ChIP chip and in vitro footprint analyses revealed the Efg1 recognition sequence (EGR‐box) TATGCATA in the yeast growth form of this human fungal pathogen. Upstream regions of EFG1 and genes encoding transcriptional regulators of hyphal growth including TCC1 , CZF1 , TEC1 , DEF1 and NRG1 contained EGR‐ and/or EGR‐like boxes. Unexpectedly, after brief hyphal induction the genome‐wide Efg1 binding pattern was completely altered and new binding sites of yet unknown specificity had appeared. Hyphal induction abolished Efg1 accumulation on EFG1 and TCC1 promoters and led to rapid decline of both transcripts, although the Efg1 protein persisted in cells. While EFG1 promoter activity in the yeast growth form did not depend on bound Efg1, its downregulation under hyphal induction depended on the presence of Efg1 and the protein kinase A isoform Tpk2. Deletion analyses of the EFG1 upstream region revealed that none of its resident EGR‐boxes is uniquely responsible for EFG1 promoter downregulation. These results suggest different binding specificities of Efg1 in yeast growth and in hyphal induction and suggest a brief time window following hyphal induction, in which Efg1 exerts its repressive effect on target promoters.