The ets family of genes encode transcription factors that recognize the GGAA core sequence in various promoters and enhancers and activate transcription via binding to these sequences. Several ets proteins bind to DNA as monomers; however, it has been reported that DNA-binding, as well as transactivation by the ets family proteins, is increased by other cellular factors. Previously, we have shown that the overexpression of ets-1 and ets-2 genes transforms NIH3T3 cells and these transformants, 7AQS2.1 (ets-1) and 3A (ets-2), produce high levels of the ets proteins. In order to isolate ets-1 and ets-2-responsive genes in these transformed cells, we prepared RNA from 7AQS2.1, 3A and normal NIH3T3 cell lines and analyzed by the differential display technique. Sixteen clones were analyzed by DNA sequence analysis and most of them appeared to be unique because their DNA sequences did not match with the known genes present in the gene bank. Among the known genes, one clone appeared to be identical to the CArG box-binding factor, CBF. In addition, we performed the whole genome polymerase chain reaction and isolated various genomic fragments that bind to the ets-1 protein in the presence of a specific monoclonal antibody. The immune complex bound DNA fragments were cloned in pBS SK+ and subjected to DNA sequence analysis. Most of the clones showed the presence of ets binding sites (CAGGAAG). Of the 21 clones sequenced, 17 of them represented unique DNA sequences. Three clones turned out to be fragments derived from the human serglycin, T-cell receptor CD3-gamma and apolipoprotein gene promoters. Interestingly, the human serglycin promoter fragment showed multiple ets- binding sites similar to those shown previously in the EndoA enhancer.
