The chicken cellular progenitor of the v-ets oncogene, p68c-ets-1, is a nuclear DNA-binding protein not expressed in lymphoid cells of the spleen.

The chicken cellular c-ets-1 locus encodes for two related proteins generated by alternative splicing: the widely expressed p54c-ets-1 protein and the cellular homolog of the v-ets-encoded domain of the E26-transforming protein P135gag-myb-ets, p68c-ets-1 which has been found so far only in the spleen. We have prepared a new site specific antiserum directed against the amino-terminus of p68c-ets-1, which is highly hydrophobic by contrast to the hydrophilic NH2 terminus of p54c-ets-1. This antiserum specifically immunoprecipitated p68c-ets-1 and P135gag-myb-ets only in denaturing and reducing conditions. Despite these biochemical differences at their amino-terminal parts, p68c-ets-1, as p54c-ets-1, is a nuclear protein able to bind to DNA in vitro. Unlike p54c-ets-1 which is expressed at high levels in T- and B-lymphoid cells, p68c-ets-1 is not expressed in lymphoid cells of the spleen. Thus, the two c-ets-1 encoded proteins, although both exhibiting DNA-binding properties in vitro, display differences both in the nature of their specific NH2 termini, and in their level and pattern of expression.