Multiple protein/protein and protein/RNA interactions suggest roles for yeast DNA/RNA helicase Sen1p in transcription, transcription-coupled DNA repair and RNA processing.
Sen1p in Saccharomyces cerevisiae is a Type I DNA/RNA helicase. Mutations in the helicase domain perturb accumulation of diverse RNA classes, and Sen1p has been implicated in 3' end formation of non-coding RNAs. Using a combination of global and candidate-specific two hybrid screens, eight proteins were identified that interact with Sen1p. Interactions with three of the proteins were analyzed further: Rpo21p(Rpb1p), a subunit of RNA polymerase II, Rad2p, a deoxyribonuclease required in DNA repair, and Rnt1p (RNase III), an endoribonuclease required for RNA maturation. For all three interactions, the two-hybrid results were confirmed by co-immunoprecipitation experiments. Genetic tests designed to assess the biological significance of the interactions indicate that Sen1p plays functionally significant roles in transcription and transcription-coupled DNA repair. To investigate the potential role of Sen1p in RNA processing and to assess the functional significance of the Sen1p/Rnt1p interaction, we examined U5 snRNA biogenesis. We provide evidence that Sen1p functions in concert with Rnt1p and the exosome at a late step in 3' end formation of one of the two mature forms of U5 snRNA but not the other. The protein-protein and protein-RNA interactions reported here suggest that the DNA/RNA helicase activity of Sen1p is utilized for several different purposes in multiple gene expression pathways.
Ursic
Doris
D
Laboratories of Molecular Biology and Genetics, R.M. Bock Laboratories, 1525 Linden Drive, University of Wisconsin, Madison, WI 53706, USA.
Chinchilla
Karen
K
Finkel
Jonathan S
JS
Culbertson
Michael R
MR
D002455:Cell Division; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004260:DNA Repair; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D046911:Macromolecular Substances; D009154:Mutation; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism; D043244:Ribonuclease III / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D005656:Fungal Proteins; D046911:Macromolecular Substances; D012331:RNA, Fungal; D012342:RNA, Small Nuclear; D029701:Saccharomyces cerevisiae Proteins; C405485:U5 small nuclear RNA; C468367:RNT1 protein, S cerevisiae; D043244:Ribonuclease III; C542347:SEN1 protein, S cerevisiae; D004265:DNA Helicases; D020365:RNA Helicases