Expression of small RNAs in Rhizobiales and protection of a small RNA and its degradation products by Hfq in Sinorhizobium meliloti

Voß, Björn; Hölscher, M.; Baumgarth, Birgit; Kalbfleisch, Andreas; Kaya, Ceren; Hess, Wolfgang R.; Becker, Anke; Evguenieva‐Hackenberg, Elena

doi:10.1016/j.bbrc.2009.09.125

Cited by 35 publications

(45 citation statements)

References 21 publications

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“…Thus, a similar mechanism may operate at the 5= UTR of sinI. To check for the involvement of Hfq, we used a 2011⌬hfq mutant (54). We detected larger AHL amounts in cultures of this mutant than in the parental strain, 2011 (data not shown), in agreement with the previously reported higher sinI mRNA and AHL levels in the absence of a functional hfq gene in S. meliloti (25).…”

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confidence: 86%

RNase E Affects the Expression of the Acyl-Homoserine Lactone Synthase Gene sinI in Sinorhizobium meliloti

et al. 2014

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c Quorum sensing of Sinorhizobium meliloti relies on N-acyl-homoserine lactones (AHLs) as autoinducers. AHL production increases at high population density, and this depends on the AHL synthase SinI and two transcriptional regulators, SinR and ExpR. Our study demonstrates that ectopic expression of the gene rne, coding for RNase E, an endoribonuclease that is probably essential for growth, prevents the accumulation of AHLs at detectable levels. The ectopic rne expression led to a higher level of rne mRNA and a lower level of sinI mRNA independently of the presence of ExpR, the AHL receptor, and AHLs. In line with this, IPTG (isopropyl-␤-D-thiogalactopyranoside)-induced overexpression of rne resulted in a shorter half-life of sinI mRNA and a strong reduction of AHL accumulation. Moreover, using translational sinI-egfp fusions, we found that sinI expression is specifically decreased upon induced overexpression of rne, independently of the presence of the global posttranscriptional regulator Hfq. The 28-nucleotide 5= untranslated region (UTR) of sinI mRNA was sufficient for this effect. Random amplification of 5= cDNA ends (5=-RACE) analyses revealed a potential RNase E cleavage site at position ؉24 between the Shine-Dalgarno site and the translation start site. We postulate therefore that RNase E-dependent degradation of sinI mRNA from the 5= end is one of the steps mediating a high turnover of sinI mRNA, which allows the Sin quorum-sensing system to respond rapidly to changes in transcriptional control of AHL production.

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confidence: 86%

RNase E Affects the Expression of the Acyl-Homoserine Lactone Synthase Gene sinI in Sinorhizobium meliloti

et al. 2014

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“…In the photosynthetic alphaproteobacterium Rhodobacter sphaeroides, the Hfq protein plays an important role in protection against photooxidative stress (5,6). During the past 2 years, sev-eral studies on Hfq in the plant symbiont Sinorhizobium meliloti demonstrated the importance of the RNA chaperone in cell physiology and symbiosis (3,4,24,54,60,65).…”

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Hfq Influences Multiple Transport Systems and Virulence in the Plant Pathogen Agrobacterium tumefaciens

et al. 2012

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The Hfq protein mediates gene regulation by small RNAs (sRNAs) in about 50% of all bacteria. Depending on the species, phenotypic defects of an hfq mutant range from mild to severe. Here, we document that the purified Hfq protein of the plant pathogen and natural genetic engineer Agrobacterium tumefaciens binds to the previously described sRNA AbcR1 and its target mRNA atu2422 , which codes for the substrate binding protein of an ABC transporter taking up proline and γ-aminobutyric acid (GABA). Several other ABC transporter components were overproduced in an hfq mutant compared to their levels in the parental strain, suggesting that Hfq plays a major role in controlling the uptake systems and metabolic versatility of A. tumefaciens . The hfq mutant showed delayed growth, altered cell morphology, and reduced motility. Although the DNA-transferring type IV secretion system was produced, tumor formation by the mutant strain was attenuated, demonstrating an important contribution of Hfq to plant transformation by A. tumefaciens .

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“…[23][24][25][26][27][28] In the a-proteobacterium Agrobacterium tumefaciens the sRNA AbcR1, which is homologous to the Hfq-dependent sRNA SmrC16 of S. meliloti, controls the expression of a periplasmic substrate binding protein required for uptake of the plant-derived defense signal GABA. 22,23,29 Here we describe the prediction, verification and analysis of seven novel sRNAs in the Bradyrhizobium/Rhodopseudomonas lineage. Although the amount of the sRNAs was not significantly influenced by temperature, salt or oxidative stress, changes were detected at stationary phase and by the comparison of bacteroids in nodules to free-living B. japonicum USDA 110 cells.…”

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“…[19][20][21] The 6S RNA homolog of B. japonicum USDA 110 was recently identified. 22 So far, 6S RNA and tmRNA are the only sRNAs whose existence in Bradyrizobium was experimentally verified.…”

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Small RNAs of theBradyrhizobium/Rhodopseudomonaslineage and their analysis

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et al. 2012

RNA Biology

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Evguenieva-Hackenberg (2012) Small RNAs (sRNAs) play a pivotal role in bacterial gene regulation. However, the sRNAs of the vast majority of bacteria with sequenced genomes still remain unknown since sRNA genes are usually difficult to recognize and thus not annotated. Here, expression of seven sRNAs (BjrC2a, BjrC2b, BjrC2c, BjrC68, BjrC80, BjrC174 and BjrC1505) predicted by genome comparison of Bradyrhizobium and Rhodopseudomonas members, was verified by RNA gel blot hybridization, microarray and deep sequencing analyses of RNA from the soybean symbiont Bradyrhizobium japonicum USDA 110. BjrC2a, BjrC2b and BjrC2c belong to the RNA family RF00519, while the other sRNAs are novel. For some of the sRNAs we observed expression differences between free-living bacteria and bacteroids in root nodules. The amount of BjrC1505 was decreased in nodules. By contrast, the amount of BjrC2a, BjrC68, BjrC80, BjrC174 and the previously described 6S RNA was increased in nodules, and accumulation of truncated forms of these sRNAs was observed. Comparative genomics and deep sequencing suggest that BjrC2a is an antisense RNA regulating the expression of inositol-monophosphatase. The analyzed sRNAs show a different degree of conservation in Rhizobiales, and expression of homologs of BjrC2, BjrC68, BjrC1505, and 6S RNA was confirmed in the free-living purple bacterium Rhodopseudomonas palustris 5D.

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Expression of small RNAs in Rhizobiales and protection of a small RNA and its degradation products by Hfq in Sinorhizobium meliloti

Cited by 35 publications

References 21 publications

RNase E Affects the Expression of the Acyl-Homoserine Lactone Synthase Gene sinI in Sinorhizobium meliloti

RNase E Affects the Expression of the Acyl-Homoserine Lactone Synthase Gene sinI in Sinorhizobium meliloti

Hfq Influences Multiple Transport Systems and Virulence in the Plant Pathogen Agrobacterium tumefaciens

Small RNAs of theBradyrhizobium/Rhodopseudomonaslineage and their analysis

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