Protein C-ets-1 is a protein that in humans is encoded by the ETS1 gene. The protein encoded by this gene belongs to the ETS family of transcription factors. There are 28 ETS genes in humans and 27 in mice. They bind the DNA via their winged-helix-turn-helix DNA binding motif known as the Ets domain that specifically recognizes DNA sequences that contain a GGAA/T core element. However, Ets proteins differ significantly in their preference for the sequence flanking the GGAA/T core motif. For instance, the consensus sequence for Ets1 is PuCC/a-GGAA/T-GCPy. On the other hand, many natural Ets1-responsive GGAA/T elements differ from this consensus sequence. The later suggests that several other transcription factors may facilitate Ets1 binding to unfavorable DNA sequences. ChIP-Seq studies have shown that Ets1 can bind both AGGAAG and CGGAAG motifs.