Identification and characterization of human ZNF274 cDNA, which encodes a novel kruppel-type zinc-finger protein having nucleolar targeting ability

Abstract

A human cDNA encoding a novel zinc-finger protein, ZNF274, was identified by the "nuclear transportation trap" method (Ueki, N., Oda, T., Kondo, M., Yano, K., Noguchi, T., and Muramatsu, M., 1998, Nat. Biotechnol. 16: 1338-1342). Based on sequence analysis of the full-length cDNA, this novel gene has two alternative splicing forms, ZNF274a and ZNF274b, which encode putative proteins of 621 and 584 amino acids, respectively. ZNF274a contains five C2H2-type zinc-finger motifs, two KRAB-A (Kruppel-associated box) domains, and one leucine-rich domain. ZNF274b lacks the first KRAB-A domain at the N-terminus. ZNF274 mRNA is detected in various human tissues by Northern analysis. The ZNF274 gene is mapped distal to marker RP S28 1 in the human chromosome 19qter region, by RH mapping. The KRAB domains of ZNF274 exhibited transcription repressor activity when tested in GAL4 fusion protein assays. EGFP-ZNF274 fusion protein expressed in COS7 cells predominantly localized to the nucleoli. A series of deletion constructs revealed that a minimal domain consisting of the third and fourth zinc-fingers possesses nucleolar targeting ability. These results suggest that ZNF274 is a ubiquitous transcription repressor that plays a role in the nucleoli.