Structure and erythroid cell-restricted expression of a chicken cDNA encoding a novel zinc finger protein of the Cys + His class.

We report the cloning, sequence analysis and expression pattern of chGfi, a zinc finger protein (Zfp)-encoding cDNA that was isolated from a cDNA library constructed with RNA from avian erythroblastosis virus (AEV)-transformed primary chicken erythroblasts. The 1387-bp-long chGfi cDNA encodes a full-length 337-amino-acid (aa) protein that contains six zinc fingers (Zf) of the 2Cys + 2His class at its C-terminus. Immunoblotting experiments with extracts from bone marrow cells detected a 38-kDa protein that corresponds to the M(r) of 38,690 calculated for the protein deduced from chGfi. The chGfi protein is most homologous to the rat Gfi-1 showing a sequence similarity of 92% over the Zf region and only two exchanges within the N-terminal 19 aa that constitute the Gfi-1 repressor domain. Expression of chGfi is only detected in transformed primary erythroblasts, in erythroid cells of the primitive and definitive lineage and in bone marrow cells. chGfi activity does not vary significantly during differentiation of transformed primary erythroblasts of the definitive lineage. No chGfi expression is detected in cells of the myeloid and lymphoid lineages or in a total of nine different organs of adult origin. Our results indicate that chGfi expression is restricted to erythroid cells of the primitive and definitive lineage.