GENES: STRUCTURE AND REGULATION
The Small Nuclear RNA-activating Protein 190 Myb DNA Binding Domain Stimulates TATA Box-binding Protein-TATA Box Recognition*

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Human U6 small nuclear RNA (snRNA) gene transcription by RNA polymerase III requires cooperative promoter binding involving the snRNA-activating protein complex (SNAPc) and the TATA-box binding protein (TBP). To investigate the role of SNAPc for TBP function at U6 promoters, TBP recruitment assays were performed using full-length TBP and a mini-SNAPc containing SNAP43, SNAP50, and a truncated SNAP190. Mini-SNAPc efficiently recruits TBP to the U6 TATA box, and two SNAPc subunits, SNAP43 and SNAP190, directly interact with the TBP DNA binding domain. Truncated SNAP190 containing only the Myb DNA binding domain is sufficient for TBP recruitment to the TATA box. Therefore, the SNAP190 Myb domain functions both to specifically recognize the proximal sequence element present in the core promoters of human snRNA genes and to stimulate TBP recognition of the neighboring TATA box present in human U6 snRNA promoters. The SNAP190 Myb domain also stimulates complex assembly with TBP and Brf2, a subunit of a snRNA-specific TFIIIB complex. Thus, interactions between the DNA binding domains of SNAP190 and TBP at juxtaposed promoter elements define the assembly of a RNA polymerase III-specific preinitiation complex.

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Published, JBC Papers in Press, March 5, 2003, DOI 10.1074/jbc.M204247200

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This work was supported by National Institutes of Health Grant R01 GM59805 and American Cancer Society Grant RPG-00-263-01-GMC (to R. W. H.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.