Members of the zinc finger protein gene family sharing a conserved N-terminal module

Abstract

We report the isolation of human members of a sub-family of structurally related finger protein genes. These potentially encode polypeptides containing finger motifs of the Krüppel type at the C-terminus, and a conserved amino acid module at the N-terminus; because of its invariant location the latter is referred to as finger preceding box (FPB). The FPB, detected also in previously described finger proteins from human, mouse and Xenopus, extends over approximately 65 amino acids and appears to be composed of two contiguous modules: FPB-A (residues 1-42) and FPB-B (residues 43-65). The latter is absent in some of the members analyzed. Elements A and B and the zinc finger domain are encoded by separate exons in the ZNF2 gene, a human member of this sub-family. The positioning of introns within this gene is remarkable. One intron flanks and a second interrupts the first codon of the FPB-A and FPB-B modules, respectively. A third intron occurs a few nucleotides downstream of FPB-B marking its separation from the remainder of the coding sequences. This organization, together with the absence of FPB-B in some cDNAs, supports the hypothesis that mRNAs encoding polypeptides that include one, both or none of the FPB-A and FPB-B modules may be assembled through alternative splicing pathways. Northern analyses showed that members of this sub-family are expressed as multiple transcripts in several cell lines. The sequences of distinct cDNAs homologous to the ZNF2 gene indicate that alternative splicing events adjoin either coding or non coding exons to the FPB sequences.