Functional coupling of cleavage and polyadenylation with transcription of mRNA.
Cleavage and polyadenylation define the 3' ends of almost all eukaryotic mRNAs and are thought to occur during transcription. We describe a human in vitro system utilizing an immobilized template, in which transcripts in RNA polymerase II elongation complexes are efficiently cleaved and polyadenylated. Because the cleavage rate of free RNA is much slower, we conclude that cleavage is functionally coupled to transcription. Inhibition of positive transcription elongation factor b (P-TEFb) had only a modest negative effect on cleavage, as long as transcripts were long enough to contain the polyadenylation signal. In contrast, removal of the carboxyl-terminal domain of the large subunit of RNA polymerase II had a dramatic negative effect on cleavage. Unexpectedly, the 5' portion of transcript after cleavage remained associated with the template in a functional, polyadenylation-competent complex. Efficient cleavage required 5' capping by the human capping enzyme, but the reduction of cleavage seen of transcripts in COOH-terminal domain-less polymerase elongation complexes, was not because of lack of capping.
Adamson
Todd E
TE
Department of Biochemistry, University of Iowa, Iowa City, 52242, USA.
Shutt
Damon C
DC
Price
David H
DH
D000255:Adenosine Triphosphate / Q000737:chemistry; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002918:Chymotrypsin / Q000737:chemistry / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances / Q000737:chemistry; D011061:Poly A / Q000737:chemistry; D026723:Polyadenylation; D016133:Polymerase Chain Reaction; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D011189:Potassium Chloride / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry; D012319:RNA Polymerase II / Q000737:chemistry; D012333:RNA, Messenger / Q000378:metabolism*; D012492:Salts / Q000494:pharmacology; D013997:Time Factors; D014158:Transcription, Genetic
D018076:DNA, Complementary; D046911:Macromolecular Substances; D012333:RNA, Messenger; D012492:Salts; D011061:Poly A; D012313:RNA; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D004247:DNA; D042925:Positive Transcriptional Elongation Factor B; D012319:RNA Polymerase II; D002918:Chymotrypsin