The Zinc Finger Domain of Tzfp Binds to the tbs Motif Located at the Upstream Flanking Region of the Aiel (aurora-C) Kinase Gene

Abstract

Our previous studies showed that Aiel (aurora-C), is a novel testis kinase belonging to the aurora kinase family (1). In this report, we describe a testis zinc finger protein (Tzfp) that binds to the upstream flanking sequence of the Aiel gene. The mouse Tzfp gene, mapped to chromosome 7 B2-B3, encodes a 465-amino acid transcription factor containing a conserved N-terminal BTB/POZ domain and three C-terminal PLZF-like C2H2 zinc fingers. The zinc finger domain of Tzfp binds to the TGTA-CAGTGT motif (Tzfp binding site, termed tbs) located at the upstream flanking sequence of the Aiel gene by gel mobility shift, DNase I footprinting, and competition analyses. When the C-terminal zinc fingers of Tzfp were fused to the transactivation domain of VP16, the chimera activated transcription of a reporter construct containing multiple copies of the tbs. In contrast, the same chimera did not activate the reporter gene when an essential nucleotide fifth C was mutated to A at the tbs. Furthermore, we showed that the N-terminal BTB/POZ domain of TZFP has a repressor activity. Taken together, our results indicate that Tzfp recognizes a sequence-specific motif (tbs) and may play a role in the regulation of the genes carrying the tbs.