title: The Histone-Like Nucleoid Structuring Protein (H-NS) Is a Negative Regulator of the Lateral Flagellar System in the Deep-Sea Bacterium Shewanella piezotolerans WP3.
abstract: Although the histone-like nucleoid structuring protein (H-NS) is well known for its involvement in the adaptation of mesophilic bacteria, such as Escherichia coli, to cold environments and high-pressure stress, an understanding of the role of H-NS in the cold-adapted benthic microorganisms that live in the deep-sea ecosystem, which covers approximately 60% of the earth's surface, is still lacking. In this study, we characterized the function of H-NS in Shewanella piezotolerans WP3, which was isolated from West Pacific sediment at a depth of 1,914 m. Anhns gene deletion mutant (WP3Δhns) was constructed, and comparative whole-genome microarray analysis was performed. H-NS had a significant influence (fold change, >2) on the expression of a variety of WP3 genes (274 and 280 genes were upregulated and downregulated, respectively), particularly genes related to energy production and conversion. Notably, WP3Δhnsexhibited higher expression levels of lateral flagellar genes than WP3 and showed enhanced swarming motility and lateral flagellar production compared to those of WP3. The DNA gel mobility shift experiment showed that H-NS bound specifically to the promoter of lateral flagellar genes. Moreover, the high-affinity binding sequences of H-NS were identified by DNase I protection footprinting, and the results support the "binding and spreading" model for H-NS functioning. To our knowledge, this is the first attempt to characterize the function of the universal regulator H-NS in a deep-sea bacterium. Our data revealed that H-NS has a novel function as a repressor of the expression of genes related to the energy-consuming secondary flagellar system and to swarming motility.
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Huahua
authors.initials: H
authors.lastname: Jian
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Guanpeng
authors.initials: G
authors.lastname: Xu
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, People's Republic of China.
authors.forename: Yingbao
authors.initials: Y
authors.lastname: Gai
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China xoxiang@sjtu.edu.cn.|State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Xiao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005407:Flagella / Q000502:physiology*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D019015:Geologic Sediments; D008124:Locomotion; D046228:Microarray Analysis; D001678:Organelle Biogenesis; D010140:Pacific Ocean; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020592:Shewanella / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria