A model for gene evolution of the ets-1/ets-2 transcription factors based on structural and functional homologies.

The chicken c-ets-1 locus encodes two transcription factors, p54c-ets-1 and p68c-ets-1 that differ in their N-termini, encoded respectively by the I54 and alpha beta exons. p68c-ets-1 equivalents are only found in birds and reptiles while p54c-ets-1 is widely conserved in vertebrates, from amphibians to mammals. Thus, the classical view concerning the evolution of the c-ets-1 gene has been to consider that I54 is of ancient origin whereas alpha and beta, which provide an additional activating domain in p68c-ets-1, would have been acquired much more recently.

A residue of the ETS domain mutated in the v-ets oncogene is essential for the DNA-binding and transactivating properties of the ETS-1 and ETS-2 proteins.

The c-ets-1 locus encodes two transcription factors, p54c-ets-1 and p68c-ets-1 that recognize purine-rich motifs. The v-ets oncogene of the avian retrovirus E26 differs from its cellular progenitor p68c-ets-1 by two amino acid substitutions (alanine 285 and isoleucine 445 in c-ets-1 both substituted by valine in v-ets, mutations A and B respectively) and its carboxy-terminal end (mutation C). The B mutation affects a well conserved residue in the carboxy-terminal 85 amino acids, ETS DNA-binding domain.