title: A role for a small stable RNA in modulating the activity of DNA-binding proteins.
abstract: The 10Sa RNA, encoded by the E. coli ssrA gene, appears to modulate action of some DNA-binding proteins. When ssrA is inactivated, lacZ expression from the lac operon, as well as galK from a gal operon fused to a phage lambda promoter, is reduced from that observed in bacteria wild-type for ssrA. These differences are not observed if the relevant repressor is inactive, suggesting that in the absence of 10Sa RNA binding of LacI and lambda cI repressors is enhanced. Gel mobility shifts show that 10Sa RNA binds these repressors and that an excess of 10Sa RNA competes for binding of lambda cI with a DNA fragment containing the OR2 repressor-binding sequence. Similar observations were made in studies of the E. coli LexA repressor and phage P22 C1 transcription activator proteins. These results suggest that direct interaction with 10Sa RNA may explain this modulation of protein-DNA interactions.
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Retallack
authors.forename: D I
authors.initials: DI
authors.lastname: Friedman
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D056968:Lac Repressors; D008969:Molecular Sequence Data; D011485:Protein Binding; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012697:Serine Endopeptidases; D014764:Viral Proteins / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D056968:Lac Repressors; D012329:RNA, Bacterial; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D000099160:LexA Repressor Protein; C539064:LacI protein, E coli; C016649:phage repressor proteins; C096222:tmRNA; C075601:transcription activator protein C1, Enterobacteria phage P22