A DNA binding protein that recognizes oligo(dA).oligo(dT) tracts

Oligo(dA).oligo(dT) tracts are common intergenic sequences in many organisms. In the yeast Saccharomyces cerevisiae, these sequences have been shown to influence transcription of adjacent genes. We have purified an oligo(dA).oligo(dT)-binding protein from S. cerevisiae and cloned its gene. This protein, which has been named datin, requires at least 9-11 bp of oligo(dA).oligo(dT) DNA for high affinity binding. The gene for datin (the DAT gene) encodes a 248-residue protein which contains a number of repeated sequence motifs. Datin purified from yeast corresponds to the N-terminal half of the DAT gene product. Null mutants in the DAT gene are viable but phenotypically distinguishable from congenic wild-type strains. We discuss unusual structural features and biochemical properties of datin in relation to its possible functions.