title: Regulation of a polyamine transporter by the conserved 3' UTR-derived sRNA SorX confers resistance to singlet oxygen and organic hydroperoxides in Rhodobacter sphaeroides.
abstract: Singlet oxygen is generated by bacteriochlorophylls when light and oxygen are simultaneously present in Rhodobacter sphaeroides. Singlet oxygen triggers a specific response that is partly regulated by the alternative sigma factor RpoHI/HII. The sRNA RSs2461 has previously been identified as an RpoHI/HII-dependent sRNA and is derived from the 3' UTR of the mRNA for an OmpR-type transcriptional regulator. Similar to the RpoHI/HII-dependent CcsR and SorY sRNAs, RSs2461 affects the resistance of R. sphaeroides against singlet oxygen and was therefore renamed here SorX. Furthermore, SorX has a strong impact on resistance against organic hydroperoxides that usually occur as secondary damages downstream of singlet oxygen. The 75-nt SorX 3' fragment, which is generated by RNase E cleavage and highly conserved among related species, represents the functional entity. A target search identified potA mRNA, which encodes a subunit of a polyamine transporter, as a direct SorX target and stress resistance via SorX could be linked to potA. The PotABCD transporter is an uptake system for spermidine in E. coli. While spermidine is generally described as beneficial during oxidative stress, we observed significantly increased sensitivity of R. sphaeroides to organic hydroperoxides in the presence of spermidine. We therefore propose that the diminished import of spermidine, due to down-regulation of potA by SorX, counteracts oxidative stress. Together with results from other studies this underlines the importance of regulated transport to bacterial stress defense.
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Tao
authors.initials: T
authors.lastname: Peng
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Bork A
authors.initials: BA
authors.lastname: Berghoff
authors.affiliation: b Department of Microbiology , Pusan National University , Busan , Korea.
authors.forename: Jeong-Il
authors.initials: JI
authors.lastname: Oh
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Lennart
authors.initials: L
authors.lastname: Weber
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Schirmer
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schwarz
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Glaeser
authors.affiliation: a Institut für Mikrobiologie und Molekularbiologie, IFZ, Universität Giessen , Giessen , Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Klug
mesh_terms: D020413:3' Untranslated Regions; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D018384:Oxidative Stress; D010545:Peroxides / Q000494:pharmacology*; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000235:genetics* / Q000378:metabolism; D026082:Singlet Oxygen / Q000494:pharmacology*; D013095:Spermidine / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D001426:Bacterial Proteins; D010545:Peroxides; D012329:RNA, Bacterial; D026082:Singlet Oxygen; D013095:Spermidine
keywords: 3′ UTR-derived; Hfq; Rhodobacter sphaeroides; organic hydroperoxide; polyamine transporter; potA; singlet oxygen; small RNA