Identification of a 3'-->5' exonuclease activity associated with human RNA polymerase II.
Human RNA polymerase II is shown to be associated with a 3'-->5' exonuclease activity that removes nucleoside 5'-monophosphates from the 3' end of the transcripts in isolated ternary complexes. This activity is stimulated by SII, a protein that acts as a transcription elongation factor in vitro. In addition, we show that another transcription factor, TFIIF, stimulates a competing pyrophosphorolysis reaction. These findings raise interesting questions about the roles of these activities in vivo, including the possibility that this RNA polymerase may proofread the nascent transcript.
Department of Biology, University of Oregon, Eugene 97403.
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D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism; D011756:Diphosphates / Q000378:metabolism; D005095:Exoribonucleases / Q000378:metabolism*; D006801:Humans; D012319:RNA Polymerase II / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*; D035165:Transcription Factors, General; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors
D011756:Diphosphates; D014157:Transcription Factors; D035165:Transcription Factors, General; D019473:Transcription Factors, TFII; D035602:Transcriptional Elongation Factors; C018648:transcription factor S-II; D012319:RNA Polymerase II; D005095:Exoribonucleases; C056604:transcription factor TFIIF