DIRECT ANALYSIS OF NATIVE AND CHIMERIC GATA SPECIFIC DNA-BINDING PROTEINS FROM ASPERGILLUS-NIDULANS

In Aspergillus nidulans the regulatory gene areA is responsible for me diating nitrogen metabolite repression. The areA product (AREA) repres ents an example of the GATA family of DNA binding proteins, which are characterised by the presence of a GATA domain consisting of a zinc fi nger within a highly conserved region of 52 amino acids. Among the oth er transcription factors included in this family is the principal eryt hroid transcription factor, GATA-1, which contains two GATA domains. I n order to demonstrate high specificity binding of native AREA to DNA containing the sequence -GATA-, and investigate the presence in A.nidu lans of other proteins with related specificities, we have used gel mo bility shift assays. Both AREA-dependent and independent complexes hav e been identified. Two strains bearing chimeric genes were also charac terised. In these, the region encoding the native GATA domain of AREA was replaced by sequences from murine GATA-1 cDNA encoding either the equivalent C-terminal domain or both the N and C-terminal domains. Str ains bearing the areA::NC-GATA construct, which includes the sequence encoding both the N and C-terminal domains of GATA-1, leads to a prono unced increase in one of two AREA-dependent complexes and implicates t he N-terminal domain of GATA-1 in mediating protein-protein interactio ns.