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 RPS281 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.