A novel RNA polymerase I-dependent RNase activity that shortens nascent transcripts from the 3' end.
A novel RNase activity was identified in a yeast RNA polymerase I (pol I) in vitro transcription system. Transcript cleavage occurred at the 3' end and was dependent on the presence of ternary pol I/DNA/RNA complexes and an additional protein factor not identical to transcription factor IIS (TFIIS). Transcript cleavage was observed both on arrested complexes at the linearized ends of the transcribed DNA and on intrinsic blocks of the DNA template. Shortened transcripts that remained associated within the ternary complexes were capable of resuming RNA chain elongation. Possible functions of the nuclease for transcript elongation or termination are discussed.
Institut für Biochemie I, Universität Heidelberg, Germany. IM4@ix.urz.uni-heidelberg.de
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Tschochner
D001483:Base Sequence; D004271:DNA, Fungal / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011485:Protein Binding; D012318:RNA Polymerase I / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D014157:Transcription Factors / Q000378:metabolism; D035165:Transcription Factors, General; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors
D004271:DNA, Fungal; D009838:Oligodeoxyribonucleotides; D012331:RNA, Fungal; D014157:Transcription Factors; D035165:Transcription Factors, General; D035602:Transcriptional Elongation Factors; C018648:transcription factor S-II; D012318:RNA Polymerase I; D012260:Ribonucleases