title: Physiological Function of Rac Prophage During Biofilm Formation and Regulation of Rac Excision in Escherichia coli K-12.
abstract: Rac or rac-like prophage harbors many genes with important physiological functions, while it remains excision-proficient in several bacterial strains including Escherichia coli, Salmonella spp. and Shigella spp. Here, we found that rac excision is induced during biofilm formation, and the isogenic stain without rac is more motile and forms more biofilms in nutrient-rich medium at early stages in E. coli K-12. Additionally, the presence of rac genes increases cell lysis during biofilm development. In most E. coli strains, rac is integrated into the ttcA gene which encodes a tRNA-thioltransferase. Rac excision in E. coli K-12 leads to a functional change of TtcA, which results in reduced fitness in the presence of carbenicillin. Additionally, we demonstrate that YdaQ (renamed as XisR) is the excisionase of rac in E. coli K-12, and that rac excision is induced by the stationary sigma factor RpoS through inducing xisR expression. Taken together, our results reveal that upon rac integration, not only are new genes introduced into the host, but also there is a functional change in a host enzyme. Hence, rac excision is tightly regulated by host factors to control its stability in the host genome under different stress conditions.
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yangmei
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
authors.forename: Yunxue
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhenshun
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Baiyuan
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802-4400.|Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802-4400.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Wood
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
authors.forename: Xingsheng
authors.initials: X
authors.lastname: Cai
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
authors.forename: Xiaoxue
authors.initials: X
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D002228:Carbenicillin / Q000494:pharmacology; D004254:DNA Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism*; D048168:Escherichia coli K12 / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000821:virology; D029968:Escherichia coli Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D008969:Molecular Sequence Data; D039002:Prophages / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012808:Sigma Factor / Q000235:genetics; D013466:Sulfurtransferases / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014775:Virus Activation / Q000235:genetics* / Q000502:physiology; D057074:Virus Release / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012808:Sigma Factor; D014764:Viral Proteins; C069567:sigma factor KatF protein, Bacteria; D004254:DNA Nucleotidyltransferases; C063911:excisionase; D013466:Sulfurtransferases; C000591238:TtcA protein, E coli; D002228:Carbenicillin