Activation of RNA Polymerase II by Topologically Linked DNA-Tracking Proteins

• Published in: Proceedings of the National Academy of Sciences - PNAS 1997-06, Vol.94 (13), p.6718-6723
• Main Authors: Ouhammouch, Mohamed, Sayre, Michael H., Kadonaga, James T., Geiduschek, E. Peter
• Format: Article
• Language: English
• Subjects: Animals; Biochemistry; Biological Sciences; DNA; DNA Polymerase III - genetics; DNA Polymerase III - metabolism; Drosophila; Drosophila melanogaster; Enzyme Activation; Enzymes; Escherichia coli; herpes simplex virus; Histones; Plasmids; Proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Repressor proteins; Ribonucleic acid; RNA; RNA Polymerase II - genetics; RNA Polymerase II - metabolism; Saccharomyces cerevisiae; Topology; Transcriptional Activation
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.13.6718

Almost all proteins mediating transcriptional activation from promoter-distal sites attach themselves, directly or indirectly, to specific DNA sequence elements. Nevertheless, a single instance of activation by a prokaryotic topologically linked DNA-tracking protein has also been demonstrated. The scope of the latter class of transcriptional activators is broadened in this work. Heterologous fusion proteins linking the transcriptional activation domain of herpes simplex virus VP16 protein to the sliding clamp protein β of the Escherichia coli DNA polymerase III holoenzyme are shown to function as topologically DNA-linked activators of yeast and Drosophila RNA polymerase II. The β :VP16 fusion proteins must be loaded onto DNA by the clamp-loading E. coli γ complex to be transcriptionally active, but they do not occupy fixed sites on the DNA. The DNA-loading sites of these activators have all the properties of enhancers: they can be inverted and their locations relative to the transcriptional start site are freely adjustable.