title: Marking the start site of RNA polymerase III transcription: the role of constraint, compaction and continuity of the transcribed DNA strand.
abstract: The effects of breaks in the individual strands of an RNA polymerase III promoter on initiation of transcription have been examined. Single breaks have been introduced at 2 bp intervals in a 24 bp segment that spans the transcriptional start site of the U6 snRNA gene promoter. Their effects on transcription are asymmetrically distributed: transcribed (template) strand breaks downstream of bp-14 (relative to the normal start as +1) systematically shift the start site, evidently by disrupting the normal mechanism that measures distance from DNA-bound TBP. Breaks placed close to the normal start site very strongly inhibit transcription. Breaks in the non-transcribed strand generate only minor effects on transcription. A structure-based model interprets these observations and explains how the transcribed strand is used to locate the transcriptional start site.
authors.affiliation: Division of Biology and Center for Molecular Genetics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0634, USA. agrove@lsu.edu
authors.forename: Anne
authors.initials: A
authors.lastname: Grove
authors.forename: Morgan S
authors.initials: MS
authors.lastname: Adessa
authors.forename: E Peter
authors.initials: EP
authors.lastname: Geiduschek
authors.forename: George A
authors.initials: GA
authors.lastname: Kassavetis
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D015342:DNA Probes; D011401:Promoter Regions, Genetic; D012320:RNA Polymerase III / Q000235:genetics*; D013698:Templates, Genetic; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D015342:DNA Probes; D035361:Transcription Factor TFIIIB; D014157:Transcription Factors; D004247:DNA; D012320:RNA Polymerase III