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 chG fi, 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. Immu noblotting experiments with extracts from bone marrow cells detected a 38-kDa protein that corresponds to the M-r of 38 690 calculated for t he 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 th e Gfi-1 repressor domain. Expression of chGfi is only detected in tran sformed 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 eryth roblasts of the definitive lineage. No chGfi expression is detected in cells of the myeloid and lymphoid lineages or in a total of nine diff erent organs of adult origin. Our results indicate that chGfi expressi on is restricted to erythroid cells of the primitive and definitive li neage. (C) 1997 Elsevier Science B.V.