Analysis of the distribution of protein binding DNA motives in the vicinity of the 3'-side chicken alpha-globin enhancer

Abstract

DNA-protein interactions in the vicinity of the 3'-side chicken alpha-globin enhancer were analyzed in vitro. Downstream of the three GATA-1 motifs which constitute the core enhancer, a 4th homology box, containing two further DNA binding motifs, was found by sequence alignment between duck and chicken. One was identified as being a fourth GATA-1 motif in opposite polarity, while the other contains a putative AP-1/NF-E2 binding site. In addition, it was found that several GGTGG motifs interacting with nuclear factors are interspersed between the different GATA-1 sites. When nuclear extracts from chicken erythroblasts transformed by an AEV ts-mutant (clone HD3) or from adult chicken erythrocytes were compared, different protein factors were found to interact with these DNA motifs in DNase I footprinting and electrophoretic retardation experiments. These results are discussed in terms of a general distribution of protein-binding DNA sequences and the presence of nuclear factors in the majority of globin and also some non-globin gene control regions.