title: RNase E and RNase J are needed for S-adenosylmethionine homeostasis in Sinorhizobium meliloti.
abstract: The ribonucleases (RNases) E and J play major roles in E. coli and Bacillus subtilis, respectively, and co-exist in Sinorhizobium meliloti. We analysed S. meliloti 2011 mutants with mini-Tn5 insertions in the corresponding genes rne and rnj and found many overlapping effects. We observed similar changes in mRNA levels, including lower mRNA levels of the motility and chemotaxis related genes flaA, flgB and cheR and higher levels of ndvA (important for glucan export). The acyl-homoserine lactone (AHL) levels were also higher during exponential growth in both RNase mutants, despite no increase in the expression of the sinI AHL synthase gene. Furthermore, several RNAs from both mutants migrated aberrantly in denaturing gels at 300 V but not under stronger denaturing conditions at 1300 V. The similarities between the two mutants could be explained by increased levels of the key methyl donor S-adenosylmethionine (SAM), since this may result in faster AHL synthesis leading to higher AHL accumulation as well as in uncontrolled methylation of macromolecules including RNA, which may strengthen RNA secondary structures. Indeed, we found that in both mutants the N6-methyladenosine content was increased almost threefold and the SAM level was increased at least sevenfold. Complementation by induced ectopic expression of the respective RNase restored the AHL and SAM levels in each of the mutants. In summary, our data show that both RNase E and RNase J are needed for SAM homeostasis in S. meliloti.
authors.affiliation: Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.|Present address: CNRS, Institut de Biologie Physico-Chimique, 13 Rue Pierre et Marie Curie, 75005 Paris, France.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Baumgardt
authors.affiliation: Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Melior
authors.affiliation: Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.|Present address: Institute of Medical Virology, Biomedical Research Center, Justus Liebig University, Schubertstr. 81, D 35392 Giessen, Germany.
authors.forename: Ramakanth
authors.initials: R
authors.lastname: Madhugiri
authors.affiliation: Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Thalmann
authors.affiliation: Institute of Phytopathology and Applied Zoology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.|Present address: Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Brunswick, Germany.
authors.forename: Adam
authors.initials: A
authors.lastname: Schikora
authors.affiliation: Centre of Synthetic Microbiology, Hans-Meerwein-Straße 6, D-35043 Marburg, Germany.
authors.forename: Matthew
authors.initials: M
authors.lastname: McIntosh
authors.affiliation: Centre of Synthetic Microbiology, Hans-Meerwein-Straße 6, D-35043 Marburg, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Becker
authors.affiliation: Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Evguenieva-Hackenberg
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D004722:Endoribonucleases / Q000235:genetics*; D005408:Flagellin / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008745:Methylation; D008780:Methyltransferases / Q000235:genetics*; D053038:Quorum Sensing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D012333:RNA, Messenger; C056783:ndvA protein, Rhizobium meliloti; D005408:Flagellin; C067138:flaA protein, bacteria; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D004722:Endoribonucleases; C022537:ribonuclease E