The Trypanosoma brucei spliced leader RNA and rRNA gene promoters have interchangeable TbSNAP50-binding elements

Nucleic Acids Res. 2004 Feb 2;32(2):700-9. doi: 10.1093/nar/gkh231. Print 2004.

Abstract

In the protist parasite Trypanosoma brucei, the small nuclear spliced leader (SL) RNA and the large rRNAs are key molecules for mRNA maturation and protein synthesis, respectively. The SL RNA gene (SLRNA) promoter recruits RNA polymerase II and consists of a bipartite upstream sequence element (USE) and an element close to the transcription initiation site. Here, we analyzed the distal part of the ribosomal (RRNA) promoter and identified two sequence blocks which, in reverse orientation, closely resemble the SLRNA USE by both sequence and spacing. A detailed mutational analysis revealed that the ribosomal (r)USE is essential for efficient RRNA transcription in vivo and that it functions in an orientation-dependent manner. Moreover, we showed that USE and rUSE are functionally interchangeable and that rUSE stably interacted with an essential factor of SLRNA transcription. Finally, we demonstrated that the T.brucei homolog of the recently characterized transcription factor p57 of the related organism Leptomonas seymouri specifically bound to USE and rUSE. Since p57 and its T.brucei counterpart are homologous to SNAP50, a component of the human small nuclear RNA gene activation protein complex (SNAPc), both SLRNA and RRNA transcription in T.brucei may depend on a SNAPc-like transcription factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cell Line
  • DNA / genetics
  • DNA / metabolism
  • DNA-Binding Proteins / chemistry
  • Enhancer Elements, Genetic / genetics
  • Gene Expression Regulation / genetics
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed / genetics
  • Promoter Regions, Genetic / genetics*
  • Protein Binding
  • RNA Polymerase II / metabolism
  • RNA, Protozoan / biosynthesis
  • RNA, Protozoan / genetics*
  • RNA, Ribosomal / biosynthesis
  • RNA, Ribosomal / genetics*
  • RNA, Spliced Leader / biosynthesis
  • RNA, Spliced Leader / genetics*
  • Response Elements / genetics*
  • Transcription Factors / chemistry
  • Transcription Factors / metabolism*
  • Transcription, Genetic / genetics
  • Transcriptional Activation
  • Trypanosoma brucei brucei / genetics*

Substances

  • DNA-Binding Proteins
  • RNA, Protozoan
  • RNA, Ribosomal
  • RNA, Spliced Leader
  • SNAPC3 protein, human
  • Transcription Factors
  • DNA
  • RNA Polymerase II

Associated data

  • GENBANK/AJ581666