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A TFIIH-associated mediator head is a basal factor of small nuclear spliced leader RNA gene transcription in early-diverged trypanosomes.
Lee, Ju Huck; Cai, Gang; Panigrahi, Aswini K; Dunham-Ems, Star; Nguyen, Tu N; Radolf, Justin D; Asturias, Francisco J; Günzl, Arthur.
Afiliação
  • Lee JH; Department of Genetics and Developmental Biology, University of Connecticut Health Center, 400 Farmington Avenue, Farmington, CT 06030-6403, USA.
Mol Cell Biol ; 30(23): 5502-13, 2010 Dec.
Article em En | MEDLINE | ID: mdl-20876299
Genome annotation suggested that early-diverged kinetoplastids possess a reduced set of basal transcription factors. More recent work, however, on the lethal parasite Trypanosoma brucei identified extremely divergent orthologs of TBP, TFIIA, TFIIB, and TFIIH which, together with the small nuclear RNA-activating protein complex, form a transcription preinitiation complex (PIC) at the spliced leader (SL) RNA gene (SLRNA) promoter. The SL RNA is a small nuclear RNA and a trans splicing substrate for the maturation of all pre-mRNAs which is metabolized continuously to sustain gene expression. Here, we identified and biochemically characterized a novel TFIIH-associated protein complex in T. brucei (Med-T) consisting of nine subunits whose amino acid sequences are conserved only among kinetoplastid organisms. Functional analyses in vivo and in vitro demonstrated that the complex is essential for cell viability, SLRNA transcription, and PIC integrity. Molecular structure analysis of purified Med-T and Med-T/TFIIH complexes by electron microscopy revealed that Med-T corresponds to the mediator head module of higher eukaryotes. These data therefore show that mediator is a basal factor for small nuclear SL RNA gene transcription in trypanosomes and that the basal transcription function of mediator head is a characteristic feature of eukaryotes which developed early in their evolution.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Trypanosoma brucei brucei / RNA Nuclear Pequeno / Proteínas de Protozoários / RNA de Protozoário / RNA Líder para Processamento / Fator de Transcrição TFIIH Tipo de estudo: Prognostic_studies / Risk_factors_studies Idioma: En Revista: Mol Cell Biol Ano de publicação: 2010 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Trypanosoma brucei brucei / RNA Nuclear Pequeno / Proteínas de Protozoários / RNA de Protozoário / RNA Líder para Processamento / Fator de Transcrição TFIIH Tipo de estudo: Prognostic_studies / Risk_factors_studies Idioma: En Revista: Mol Cell Biol Ano de publicação: 2010 Tipo de documento: Article País de afiliação: Estados Unidos