title: The GacS/GacA signal transduction system of Pseudomonas aeruginosa acts exclusively through its control over the transcription of the RsmY and RsmZ regulatory small RNAs.
abstract: We report here the results of an analysis of the regulatory range of the GacS/GacA two-component system in Pseudomonas aeruginosa. Using microarrays, we identified a large number of genes that are regulated by the system, and detected a near complete overlap of these genes with those regulated by two small RNAs (sRNAs), RsmY and RsmZ, suggesting that the expression of all GacA-regulated genes is RsmY/Z-dependent. Using genome-wide DNA-protein interaction analyses, we identified only two genomic regions that associated specifically with GacA, located upstream of the rsmY and rsmZ genes. These results demonstrate that in P. aeruginosa, the GacS/GacA system transduces the regulatory signals to downstream genes exclusively by directly controlling the expression of only two genes rsmY and rsmZ. These two sRNAs serve as intermediates between the input signals and the output at the level of mRNA stability, although additional regulatory inputs can influence the levels of these two riboregulators. We show that the A+T-rich DNA segment upstream of rsmZ is bound and silenced by MvaT and MvaU, the global gene regulators of the H-NS family. This work highlights the importance of post-transcriptional mechanisms involving sRNAs in controlling gene expression during bacterial adaptation to different environments.
authors: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors: Anja
authors: A
authors: Brencic
authors: Kirsty A
authors: KA
authors: McFarland
authors: Heather R
authors: HR
authors: McManus
authors: Sandra
authors: S
authors: Castang
authors: Ilaria
authors: I
authors: Mogno
authors: Simon L
authors: SL
authors: Dove
authors: Stephen
authors: S
authors: Lory
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D020868:Gene Silencing; D005798:Genes, Bacterial; D005809:Genes, Regulator; D020411:Oligonucleotide Array Sequence Analysis; D010442:Peptide Chain Initiation, Translational; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism; D020871:RNA Stability; D012329:RNA, Bacterial / Q000378:metabolism; D022661:RNA, Untranslated / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C091100:GacA protein, Bacteria; C111692:MvaT protein, Pseudomonas; D012329:RNA, Bacterial; D022661:RNA, Untranslated; D015534:Trans-Activators; D014157:Transcription Factors; C074165:lemA protein, bacterial