The RNA polymerase II elongation complex. Factor-dependent transcription elongation involves nascent RNA cleavage.
Regulation of transcription elongation is an important mechanism in controlling eukaryotic gene expression. SII is an RNA polymerase II-binding protein that stimulates transcription elongation and also activates nascent transcript cleavage by RNA polymerase II in elongation complexes in vitro (Reines, D. (1992) J. Biol. Chem. 267, 3795-3800). Here we show that SII-dependent in vitro transcription through an arrest site in a human gene is preceded by nascent transcript cleavage. RNA cleavage appeared to be an obligatory step in the SII activation process. Recombinant SII activated cleavage while a truncated derivative lacking polymerase binding activity did not. Cleavage was not restricted to an elongation complex arrested at this particular site, showing that nascent RNA hydrolysis is a general property of RNA polymerase II elongation complexes. These data support a model whereby SII stimulates elongation via a ribonuclease activity of the elongation complex.
Reines
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D
Graduate Program in Biochemistry and Molecular Biology, Emory University School of Medicine, Atlanta, Georgia 30322.
Ghanouni
P
P
Li
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QQ
Mote
J
J
D000818:Animals; D001483:Base Sequence; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D012313:RNA / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012319:RNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D014158:Transcription, Genetic
D011994:Recombinant Proteins; D012313:RNA; D012319:RNA Polymerase II