Trypanosomal TBP functions with the multisubunit transcription factor tSNAP to direct spliced-leader RNA gene expression.
Protein-coding genes of trypanosomes are mainly transcribed polycistronically and cleaved into functional mRNAs in a process that requires trans splicing of a capped 39-nucleotide RNA derived from a short transcript, the spliced-leader (SL) RNA. SL RNA genes are individually transcribed from the only identified trypanosome RNA polymerase II promoter. We have purified and characterized a sequence-specific SL RNA promoter-binding complex, tSNAP(c), from the pathogenic parasite Trypanosoma brucei, which induces robust transcriptional activity within the SL RNA gene. Two tSNAP(c) subunits resemble essential components of the metazoan transcription factor SNAP(c), which directs small nuclear RNA transcription. A third subunit is unrelated to any eukaryotic protein and identifies tSNAP(c) as a unique trypanosomal transcription factor. Intriguingly, the unusual trypanosome TATA-binding protein (TBP) tightly associates with tSNAPc and is essential for SL RNA gene transcription. These findings provide the first view of the architecture of a transcriptional complex that assembles at an RNA polymerase II-dependent gene promoter in a highly divergent eukaryote.
Das
Anish
A
Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, 07103, USA.
Zhang
Qing
Q
Palenchar
Jennifer B
JB
Chatterjee
Bithi
B
Cross
George A M
GA
Bellofatto
Vivian
V
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002845:Chromatography; D004247:DNA / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D007074:Immunoglobulin G / Q000737:chemistry; D047468:Immunoprecipitation; D066298:In Vitro Techniques; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism; D020038:RNA, Spliced Leader; D017386:Sequence Homology, Amino Acid; D035181:TATA-Box Binding Protein / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014346:Trypanosoma brucei brucei
D007074:Immunoglobulin G; D010455:Peptides; D020038:RNA, Spliced Leader; C106703:SNAPC protein complex, human; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D012313:RNA; D004247:DNA; D012319:RNA Polymerase II