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A zinc finger protein that interacts with Xenopus TATA-binding protein was previously isolated by a yeast two-hybrid screen and found to serve as a transcriptional repressor. The gene was designated the negatively regulating zinc finger protein gene (NZFP). Herein, NZFP was found to be expressed maternally. After gastrulation, the level of NZFP mRNA decreased significantly throughout the neurula stage. However, mRNA levels increased at stage 35 and then began to decrease at stage 48. Eventually, no NZFP mRNA was observed in adult tissues except in the ovary. NZFP mRNA was detected in the animal hemisphere during gastrulation and observed in the neural ectoderm at the neurula stage. At the tailbud stage, NZFP was highly expressed in the head tissues such as brain, eyes, otic vesicles, lateral line placodes, and branchial arches, but weakly in somites. Depletion of NZFP in the embryos using RNA interference caused premature death at the gastrula stage or induced secondary partial axis after gastrulation. These results strongly suggest that NZFP is an essential transcription factor involved in the cell movement during gastrulation and the formation of the dorsal axis during early development in Xenopus. [Copyright &y& Elsevier]

We isolated a novel gene encoding a zinc finger protein from Xenopus laevis, designated NZFP that interacts with the TATA-binding protein (TBP). NZFP contains a highly conserved sequence designated finger associated box (FAX) and SUMO-1 consensus-binding motifs at the N-terminal half and 10 C2H2 type zinc finger motifs at the C-terminal half, respectively. Deletion mutants of NZFP fused with the Gal4 DNA binding domain were used to determine the function of NZFP during gene transcription by transfecting them into a Xenopus kidney cell line. Both full-length NZFP and the FAX domain repressed transcription activity by 3–5-fold. Moreover, an in vitro pull-down assay showed that the C-terminal core domain of TBP makes direct contact with the N-terminal portion of NZFP. We also found through chromatin immunoprecipitation experiments that the interaction between NZFP and TBP inhibits binding of TFIIA and TFIIB. These data strongly suggest that the repression by NZFP occurs through its binding to both DNA and TBP and the resulting NZFP–TBP–promoter complex inhibits preinitiation complex assembly by preventing binding of TFIIA and TFIIB. [Copyright &y& Elsevier]