Polynucleotide phosphorylase functions both as a 3' right-arrow 5' exonuclease and a poly(A) polymerase in Escherichiacoli
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Polynucleotide phosphorylase functions both as a 3* 3 5* exonuclease and a poly(A) polymerase in Escherichia coli
In vitro, polynucleotide phosphorylase of Escherichia coli can both synthesize RNA by using nucleotide diphosphates as precursors and exonucleolytically degrade RNA in the presence of inorganic phosphate. However, because of the high in vivo concentration of inorganic phosphate in exponentially growing cells, it has been assumed that the enzyme works exclusively as an exonuclease. Here we demon...
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The yeast 5'-3' exonuclease Rat1p functions during transcription elongation by RNA polymerase II.
Termination of RNA polymerase II (RNAPII) transcription of protein-coding genes occurs downstream of cleavage/polyadenylation sites. According to the "torpedo" model, the 5'-3' exonuclease Rat1p/Xrn2p attacks the newly formed 5' end of the cleaved pre-mRNA, causing the still transcribing RNAPII to terminate. Here we demonstrate a similar role of S. cerevisiae Rat1p within the gene body. We find...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2000
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.220295997