title: The σ54-dependent two-component system regulating sulfur oxidization (Sox) system in Acidithiobacillus caldus and some chemolithotrophic bacteria.
abstract: The sulfur oxidization (Sox) system is the central sulfur oxidization pathway of phototrophic and chemotrophic sulfur-oxidizing bacteria. Regulation and function of the Sox system in the chemotrophic Paracoccus pantotrophus has been elucidated; however, to date, no information is available on the regulation of this system in the chemolithotrophic Acidithiobacillus caldus, which is widely utilized in bioleaching. We described the novel tspSR-sox-like clusters in A. caldus and other chemolithotrophic sulfur-oxidizing bacteria containing Sox systems. The highly homologous σ54-dependent two-component signaling system (TspS/R), upstream of the sox operons in these novel clusters, was identified by phylogenetic analyses. A typical σ54-dependent promoter, P1, was identified upstream of soxX-I in the sox-I cluster of A. caldus MTH-04. The transcriptional start site (G) and the -12/-24 regions (GC/GG) of P1were determined by rapid amplification of cDNA ends (5'RACE), and the upstream activator sequences (UASs; TGTCCCAAATGGGACA) were confirmed by electrophoretic mobility shift assays (EMSAs) in vitro and by UAS-probe-plasmids assays in vivo. Sequence analysis of promoter regions in tspSR-sox-like clusters revealed that there were similar σ54-dependent promoters upstream of the soxX genes. Based on our results, we proposed a TspSR-mediated signal transduction and transcriptional regulation pathway for the Sox system in A. caldus. The regulation of σ54-dependent two-component systems (TCSs) for Sox pathways were explained for the first time in A. caldus, A. thiooxidans, T. tepidarius, and T. denitrificans, indicating the significance of modulating the sulfur oxidization in these chemolithotrophic sulfur oxidizers.
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Li-Feng
authors.initials: LF
authors.lastname: Li
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Luo-Jie
authors.initials: LJ
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Jian-Qun
authors.initials: JQ
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Xin
authors.initials: X
authors.lastname: Pang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Xiang-Mei
authors.initials: XM
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China.
authors.forename: Zhao-Bao
authors.initials: ZB
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China. jianqianglin@sdu.edu.cn.
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, People's Republic of China. linxuchen@sdu.edu.cn.
authors.forename: Lin-Xu
authors.initials: LX
authors.lastname: Chen
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic / Q000235:genetics; D051877:RNA Polymerase Sigma 54 / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics; D013455:Sulfur / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D013455:Sulfur; D051877:RNA Polymerase Sigma 54
keywords: Acidithiobacillus caldus; Sulfur metabolism; Two-component regulatory systems; bEBP; sox gene regulation; σ54