A PALINDROMIC REGULATORY SITE WITHIN VERTEBRATE GATA-1 PROMOTERS REQUIRES BOTH ZINC FINGERS OF THE GATA-1 DNA-BINDING DOMAIN FOR HIGH-AFFINITY INTERACTION

GATA-1, a transcription factor essential for the development of the er ythroid lineage, contains two adjacent highly conserved zinc finger mo tifs. The carboxy-terminal finger is necessary and sufficient for spec ific binding to the consensus GATA recognition sequence: mutant protei ns containing only the amino-terminal finger do not bind. Here we iden tify a DNA sequence (GATApal) for which the GATA-1 amino-terminal fing er makes a critical contribution to the strength of binding. The site occurs in the GATA-1 gene promoters of chickens, mice, and humans but occurs very infrequently in other vertebrate genes known to be regulat ed by GATA proteins. GATApal is a palindromic site composed of one com plete [(AIT)GATA(A/G)] and one partial (GAT) canonical motif. Deletion of the partial motif changes the site to a normal GATA site and also reduces by as much as eightfold the activity of the GATA-1 promoter in an erythroid precursor cell, We propose that GATApal is important for positive regulation of GATA-1 expression in erythroid cells.