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DNA binding site of the yeast heteromeric Ino2p/Ino4p basic helix‐loop‐helix transcription factor: structural requirements as defined by saturation mutagenesis
Author(s) -
Schüller Hans-Joachim,
Richter Karin,
Hoffmann Brigitte,
Ebbert Ronald,
Schweizer Eckhart
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00818-t
Subject(s) - basic helix loop helix , saccharomyces cerevisiae , transcription factor , yeast , biology , dna binding protein , genetics , gene , biochemistry
The inositol/choline‐responsive element (ICRE) is an 11 bp cis ‐activating sequence motif with central importance for the regulated expression of phospholipid biosynthetic genes in the yeast Saccharomyces cerevisiae . The ICRE containing the CANNTG core binding sequence (E‐box) of basic helix‐loop‐helix (bHLH) regulatory proteins is recognized by the heteromeric bHLH transcription factor Ino2p/Ino4p. In this study, we define the Ino2p/Ino4p consensus binding sequence (5′‐WYTTCAYR‐TGS‐3′) based on the characterization of all possible single nucleotide substitutions. Interestingly, this analysis also identified a single functional deviation (CACATTC) from the CANNTG core recognition element of bHLH proteins. The DNA binding specificities of different yeast bHLH proteins may now be explained by distinct nucleotide preferences especially at two positions immediately preceding the CANNTG core motif.