title: The transcription factor TFIIS zinc ribbon dipeptide Asp-Glu is critical for stimulation of elongation and RNA cleavage by RNA polymerase II.
abstract: The eukaryotic transcription factor TFIIS enhances elongation and nascent transcript cleavage activities of RNA polymerase II in a stalled elongation complex. By site-directed mutagenesis, we have demonstrated that invariant residues Asp-261 and Glu-262 of the nucleic acid-binding TFIIS Zn ribbon are critical for stimulation of both elongation and RNA cleavage activities of RNA polymerase II. Substitution of either of these residues inactivates both TFIIS functions, suggesting a related role in both activities. These acidic residues may participate in phosphoryl transfer reactions by a two-metal-ion mechanism in a manner analogous to Klenow fragment. The RNA polymerase II itself may contain a Zn ribbon, in as much as the polymerase's 15-kDa subunit contains a sequence that aligns well with the TFIIS Zn ribbon sequence, including a similarly placed pair of acidic residues.
authors.affiliation: Department of Biochemistry, University of Chicago, IL 60637.
authors.forename: C
authors.initials: C
authors.lastname: Jeon
authors.forename: H
authors.initials: H
authors.lastname: Yoon
authors.forename: K
authors.initials: K
authors.lastname: Agarwal
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D012319:RNA Polymerase II / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D035165:Transcription Factors, General; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D015032:Zinc
chemical_list: D012333:RNA, Messenger; D014157:Transcription Factors; D035165:Transcription Factors, General; D035602:Transcriptional Elongation Factors; C018648:transcription factor S-II; D012319:RNA Polymerase II; D015032:Zinc