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.
Wang
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Department of Biology, University of Oregon, Eugene 97403.
Hawley
D K
DK
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