title: A highly conserved protein of unknown function in Sinorhizobium meliloti affects sRNA regulation similar to Hfq.
abstract: The SMc01113/YbeY protein, belonging to the UPF0054 family, is highly conserved in nearly every bacterium. However, the function of these proteins still remains elusive. Our results show that SMc01113/YbeY proteins share structural similarities with the MID domain of the Argonaute (AGO) proteins, and might similarly bind to a small-RNA (sRNA) seed, making a special interaction with the phosphate on the 5'-side of the seed, suggesting they may form a component of the bacterial sRNA pathway. Indeed, eliminating SMc01113/YbeY expression in Sinorhizobium meliloti produces symbiotic and physiological phenotypes strikingly similar to those of the hfq mutant. Hfq, an RNA chaperone, is central to bacterial sRNA-pathway. We evaluated the expression of 13 target genes in the smc01113 and hfq mutants. Further, we predicted the sRNAs that may potentially target these genes, and evaluated the accumulation of nine sRNAs in WT and smc01113 and hfq mutants. Similar to hfq, smc01113 regulates the accumulation of sRNAs as well as the target mRNAs. AGOs are central components of the eukaryotic sRNA machinery and conceptual parallels between the prokaryotic and eukaryotic sRNA pathways have long been drawn. Our study provides the first line of evidence for such conceptual parallels. Furthermore, our investigation gives insights into the sRNA-mediated regulation of stress adaptation in S. meliloti.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
authors.forename: Shree P
authors.initials: SP
authors.lastname: Pandey
authors.forename: Brenda K
authors.initials: BK
authors.lastname: Minesinger
authors.forename: Janesh
authors.initials: J
authors.lastname: Kumar
authors.forename: Graham C
authors.initials: GC
authors.lastname: Walker
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001665:Binding Sites; D017124:Conserved Sequence; D015964:Gene Expression Regulation, Bacterial; D035001:Host Factor 1 Protein / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D058727:RNA, Small Untranslated / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000737:chemistry; D016415:Sequence Alignment; D016962:Sinorhizobium meliloti / Q000235:genetics* / Q000378:metabolism; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins; D035001:Host Factor 1 Protein; D058727:RNA, Small Untranslated; D034743:RNA-Induced Silencing Complex