Functional Characterization of a Trypanosoma brucei TATA-Binding Protein-Related Factor Points to a Universal Regulator of Transcription in Trypanosomes

AUTOR(ES)

Ruan, Jia-peng

FONTE

American Society for Microbiology

RESUMO

Transcriptional mechanisms remain poorly understood in trypanosomatid protozoa. In particular, there is no knowledge about the function of basal transcription factors, and there is an apparent rarity of promoters for protein-coding genes transcribed by RNA polymerase (Pol) II. Here we describe a Trypanosoma brucei factor related to the TATA-binding protein (TBP). Although this TBP-related factor (TBP-related factor 4 [TRF4]) has about 31% identity to the TBP core domain, several key residues involved in TATA box binding are not conserved. Depletion of the T. brucei TRF4 (TbTRF4) by RNA interference revealed an essential role in RNA Pol I, II, and III transcription. Using chromatin immunoprecipitation, we further showed that TRF4 is recruited to the Pol I-transcribed procyclic acidic repetitive genes, Pol II-transcribed spliced leader RNA genes, and Pol III-transcribed U-snRNA and 7SL RNA genes, thus supporting a role for TbTRF4 in transcription performed by all three nuclear RNA polymerases. Finally, a search for TRF4 binding sites in the T. brucei genome led to the identification of such sites in the 3′ portion of certain protein-coding genes, indicating a unique aspect of Pol II transcription in these organisms.

Documentos Relacionados

• Human TATA-binding protein-related factor-2 (hTRF2) stably associates with hTFIIA in HeLa cells
• TRF3, a TATA-box-binding protein-related factor, is vertebrate-specific and widely expressed
• Increased Expression of TATA-Binding Protein, the Central Transcription Factor, Can Contribute to Oncogenesis
• A Human TATA Binding Protein-Related Protein with Altered DNA Binding Specificity Inhibits Transcription from Multiple Promoters and Activators
• Cofractionation of the TATA-binding protein with the RNA polymerase III transcription factor TFIIIB.