title: Initiating nucleotide identity determines efficiency of RNA synthesis from 6S RNA templates in Bacillus subtilis but not Escherichia coli.
abstract: The 6S RNA is a non-coding small RNA that binds within the active site of housekeeping forms of RNA polymerases (e.g. Eσ(70) in Escherichia coli, Eσ(A) in Bacillus subtilis) and regulates transcription. Efficient release of RNA polymerase from 6S RNA regulation during outgrowth from stationary phase is dependent on use of 6S RNA as a template to generate a product RNA (pRNA). Interestingly, B. subtilis has two 6S RNAs, 6S-1 and 6S-2, but only 6S-1 RNA appears to be used efficiently as a template for pRNA synthesis during outgrowth. Here, we demonstrate that the identity of the initiating nucleotide is particularly important for the B. subtilis RNA polymerase to use RNA templates. Specifically, initiation with guanosine triphosphate (GTP) is required for efficient pRNA synthesis, providing mechanistic insight into why 6S-2 RNA does not support robust pRNA synthesis as it initiates with adenosine triphosphate (ATP). Intriguingly, E. coli RNA polymerase does not have a strong preference for initiating nucleotide identity. These observations highlight an important difference in biochemical properties of B. subtilis and E. coli RNA polymerases, specifically in their ability to use RNA templates efficiently, which also may reflect the differences in GTP and ATP metabolism in these two organisms.
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA.
authors.forename: Ignacio J
authors.initials: IJ
authors.lastname: Cabrera-Ostertag
authors.forename: Amy T
authors.initials: AT
authors.lastname: Cavanagh
authors.forename: Karen M
authors.initials: KM
authors.lastname: Wassarman
mesh_terms: D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006160:Guanosine Triphosphate / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated; D013379:Substrate Specificity; D014158:Transcription, Genetic
chemical_list: C411065:6S RNA; D001426:Bacterial Proteins; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D012321:DNA-Directed RNA Polymerases