A putative second cell-derived oncogene of the avian leukaemia retrovirus E26

Abstract

The acute avian leukaemia retroviruses AMV and E26 both induce myeloblastosis in vivo and transform myeloblasts in vitro. Both viruses contain the oncogene v-myb first described for AMV. Unlike AMV, E26 has the additional capacity to induce erythroblastosis in vivo and to transform erythroblasts. Previous analyses indicated that the genome of E26 also contained nucleotide sequences distinct from v-myb and unrelated to viral replicative genes. Using a molecularly cloned E26 provirus, we have now identified a novel nucleotide sequence designated v-ets (for E-twenty-six specific) of approximately 1.5 kilobase pairs (kbp) located next to v-myb. v-ets possesses all the structural characteristics of a putative new oncogene: it has a conserved cellular counterpart c-ets which is transcribed in some normal chicken cells as a major 7.5-kb polyadenylated RNA. Although our results now await elucidation of their biological significance, we propose that v-ets could be a new oncogene accounting for the additional transforming properties of E26, or potentiating the transforming properties of the v-myb oncogene.

Transformation by v-Myb

“…These viral sequences have been replaced by fragments of two di erent cellular genes, c-myb and c-ets (Leprince et al, 1983;Nunn et al, 1984). As a result, the virus encodes a single 135 kDa Gag-Myb-Ets fusion protein.…”

Molecular phylogeny of the ETS gene family

“…Numerous oncogenic versions of some ets family members have been described such as v-ets, the founder of the family which is one of the oncogene of the E26 leukemogenic virus (Leprince et al, 1983;Nunn et al, 1983). Other examples include the erg,¯i-1, FEV, ETV1 and PEA3 genes which are translocated in human myeloid leukemia and in Ewing's sarcoma (Delattre et al, 1992;Shimizu et al, 1993;Zucman et al, 1993;Jeon et al, 1995;Urano et al, 1996;Peter et al, 1997).…”

Erg proteins, transcription factors of the Ets family, form homo, heterodimers and ternary complexes via two distinct domains

“…The proto-oncogene c-ets1 is the cellular progenitor of the v-ets oncogene of the avian leukemia virus E26 and the founder member of the burgeoning ets family (Leprince et al, 1983;Nunn et al, 1983). The common feature of all Ets proteins is their DNA-binding domain (85 amino acid residues), named ETS domain and structured as a winged helix ± turn ± helix motif (Donaldson et al, 1994(Donaldson et al, , 1996Liang et al, 1994;Kodandapani et al, 1996).…”