title: SR1--a small RNA with two remarkably conserved functions.
abstract: SR1 is a dual-function sRNA that acts as a base-pairing regulatory RNA on the ahrC mRNA and as a peptide-encoding mRNA on the gapA operon. The SR1-encoded peptide SR1P binds GapA thereby stabilizing gapA mRNA. Under glycolytic conditions, SR1 transcription is repressed by CcpN and CcpA. A computer-based search identified 23 SR1 homologues in Bacillus, Geobacillus, Anoxybacillus and Brevibacillus species. All homologues share a high structural identity with Bacillus subtilis SR1, and the encoded SR1P peptides are highly similar. In the Bacillus cereus group, the sr1p region is present in triplicate or duplicate resulting in longer SR1 species. In all cases, sr1 expression is under control of CcpN, and transcriptional lacZ fusions of nine examined SR1 homologues were sensitive to glucose. Two homologues showed an additional glucose-independent repression by CcpN and an unknown factor. A total of 10 out of 11 tested SR1P homologues complemented a B. subtilis Δsr1 strain in their ability to stabilize gapA mRNA, but only five of them bound GapA tightly. In vitro binding assays with six SR1/ahrC pairs suggest that-despite divergent primary sequences-the base-pairing function is also preserved. In summary, SR1 is an sRNA with two functions that have been conserved over ≈1 billion years.
authors.affiliation: AG Bakteriengenetik, Lehrstuhl für Mikrobiologie und Mikrobengenetik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, Jena D-07743, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gimpel
authors.forename: Heike
authors.initials: H
authors.lastname: Preis
authors.forename: Emanuel
authors.initials: E
authors.lastname: Barth
authors.forename: Lydia
authors.initials: L
authors.lastname: Gramzow
authors.forename: Sabine
authors.initials: S
authors.lastname: Brantl
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D003545:Cysteine / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010455:Peptides / Q000737:chemistry; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D058727:RNA, Small Untranslated / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D026801:Synteny; D015534:Trans-Activators / Q000235:genetics
chemical_list: C120339:AhrC protein, Bacillus subtilis; D001426:Bacterial Proteins; D002352:Carrier Proteins; D010455:Peptides; D012329:RNA, Bacterial; D012333:RNA, Messenger; D058727:RNA, Small Untranslated; D012097:Repressor Proteins; D015534:Trans-Activators; D003545:Cysteine