Novel human BTB/POZ domain-containing zinc finger protein ZBTB1 inhibits transcriptional activities of CRE.

BTB/POZ protein family plays a key role in many biological processes by regulating the transcriptional activities of some downstream genes. Here, we characterized the member of C(2)H(2) type zinc finger gene, Zinc finger and BTB domain containing 1 (ZBTB1). The complete sequence of ZBTB1 cDNA contains a 2142 bp open reading frame (ORF) and encodes a 713 amino acid protein with an N-terminal BTB/POZ domain that is similar to the same domain of other known transcription regulators and eight classical zinc finger C(2)H(2) motifs in the C-terminus. Subcellular localization analysis demonstrated that ZBTB1 was localized to the nucleus, forming dot-like structures. Transcriptional activity assays showed that ZBTB1 was a transcription repressor and overexpression of ZBTB1 in the COS7 cells reduced the transcriptional activities of cAMP response element (CRE). Further studies showed that the BTB domain and ZNF motifs of ZBTB1 may both be involved in this suppression. These results suggest that ZBTB1 protein may act as a transcription repressor in the activation of CREB and cAMP-mediated signal transduction pathways to mediate cellular functions.