Specific DNA binding by c-Myb: evidence for a double helix-turn-helix-related motif

See allHide authors and affiliations

Science  06 Sep 1991:
Vol. 253, Issue 5024, pp. 1140-1143
DOI: 10.1126/science.1887237


The c-Myb protein is a sequence-specific DNA binding protein that activates transcription in hematopoietic cells. Three imperfect repeats (R1, R2, and R3) that contain regularly spaced tryptophan residues form the DNA binding domain of c-Myb. A fragment of c-Myb that contained the R2 and R3 regions bound specifically to a DNA sequence recognized by c-Myb plus ten additional base pairs at the 3' end of the element. The R2R3 fragment was predicted to contain two consecutive helix-turn-helix (HTH) motifs with unconventional turns. Mutagenesis of amino acids in R2R3 at positions that correspond to DNA-contacting amino acids in other HTH-containing proteins abolished specific DNA binding without affecting nonspecific DNA interactions.

Stay Connected to Science