Reference: Kassavetis GA, et al. (1989) Transcription factor IIIB generates extended DNA interactions in RNA polymerase III transcription complexes on tRNA genes. Mol Cell Biol 9(6):2551-66

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Abstract


Transcription complexes that assemble on tRNA genes in a crude Saccharomyces cerevisiae cell extract extend over the entire transcription unit and approximately 40 base pairs of contiguous 5'-flanking DNA. We show here that the interaction with 5'-flanking DNA is due to a protein that copurifies with transcription factor TFIIIB through several steps of purification and shares characteristic properties that are normally ascribed to TFIIIB: dependence on prior binding of TFIIIC and great stability once the TFIIIC-TFIIIB-DNA complex is formed. SUP4 gene (tRNATyr) DNA that was cut within the 5'-flanking sequence (either 31 or 28 base pairs upstream of the transcriptional start site) was no longer able to stably incorporate TFIIIB into a transcription complex. The TFIIIB-dependent 5'-flanking DNA protein interaction was predominantly not sequence specific. The extension of the transcription complex into this DNA segment does suggest two possible explanations for highly diverse effects of flanking-sequence substitutions on tRNA gene transcription: either (i) proteins that are capable of binding to these upstream DNA segments are also potentially capable of stimulating or interfering with the incorporation of TFIIIB into transcription complexes or (ii) 5'-flanking sequence influences the rate of assembly of TFIIIB into stable transcription complexes.

Reference Type
Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S.
Authors
Kassavetis GA, Riggs DL, Negri R, Nguyen LH, Geiduschek EP
Primary Lit For
TFC3 | TFC1 | TFC6 | BRF1 | TFC4 | TFC8 | BDP1 | SPT15 | TFC7 | General transcription factor TFIIIB complex | General transcription factor TFIIIC complex ... Show all
Additional Lit For
General transcription factor TFIIIB complex