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The non-canonical CTD of RNAP-II is essential for productive RNA synthesis in Trypanosoma brucei.

ABSTRACT: The carboxy-terminal domain (CTD) of the largest subunit (RPB1) of RNA polymerase II (RNAP-II) is essential for gene expression in metazoa and yeast. The canonical CTD is characterized by heptapeptide repeats. Differential phosphorylation of canonical CTD orchestrates transcriptional and co-transcriptional maturation of mRNA and snRNA. Many organisms, including trypanosomes, lack a canonical CTD. In these organisms, the CTD is called a non-canonical CTD or pseudo-CTD (PsiCTD. In the African trypanosome, Trypanosoma brucei, the PsiCTD is approximately 285 amino acids long, rich in serines and prolines, and phosphorylated. We report that T. brucei RNAP-II lacking the entire PsiCTD or containing only a 95-amino-acid-long PsiCTD failed to support cell viability. In contrast, RNAP-II with a 186-amino-acid-long PsiCTD maintained cellular growth. RNAP-II with PsiCTD truncations resulted in abortive initiation of transcription. These data establish that non-canonical CTDs play an important role in gene expression.

SUBMITTER: Das A

PROVIDER: S-EPMC2734056 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature

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The non-canonical CTD of RNAP-II is essential for productive RNA synthesis in Trypanosoma brucei.

Das Anish A Bellofatto Vivian V

PloS one 20090909 9

The carboxy-terminal domain (CTD) of the largest subunit (RPB1) of RNA polymerase II (RNAP-II) is essential for gene expression in metazoa and yeast. The canonical CTD is characterized by heptapeptide repeats. Differential phosphorylation of canonical CTD orchestrates transcriptional and co-transcriptional maturation of mRNA and snRNA. Many organisms, including trypanosomes, lack a canonical CTD. In these organisms, the CTD is called a non-canonical CTD or pseudo-CTD (PsiCTD. In the African tryp ...[more]

PMID: 19742309

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