title: Hyperphosphorylation of DegU cancels CcpA-dependent catabolite repression of rocG in Bacillus subtilis.
abstract: BACKGROUND
  The two-component regulatory system, involving the histidine sensor kinase DegS and response regulator DegU, plays an important role to control various cell processes in the transition phase of Bacillus subtilis. The degU32 allele in strain 1A95 is characterized by the accumulation of phosphorylated form of DegU (DegU-P).
  
  
  RESULTS
  Growing 1A95 cells elevated the pH of soytone-based medium more than the parental strain 168 after the onset of the transition phase. The rocG gene encodes a catabolic glutamate dehydrogenase that catalyzes one of the main ammonia-releasing reactions. Inactivation of rocG abolished 1A95-mediated increases in the pH of growth media. Thus, transcription of the rocG locus was examined, and a novel 3.7-kb transcript covering sivA, rocG, and rocA was found in 1A95 but not 168 cells. Increased intracellular fructose 1,6-bisphosphate (FBP) levels are known to activate the HPr kinase HPrK, and to induce formation of the P-Ser-HPr/CcpA complex, which binds to catabolite responsive elements (cre) and exerts CcpA-dependent catabolite repression. A putative cre found within the intergenic region between sivA and rocG, and inactivation of ccpA led to creation of the 3.7-kb transcript in 168 cells. Analyses of intermediates in central carbon metabolism revealed that intracellular FBP levels were lowered earlier in 1A95 than in 168 cells. A genome wide transcriptome analysis comparing 1A95 and 168 cells suggested similar events occurring in other catabolite repressive loci involving induction of lctE encoding lactate dehydrogenase.
  
  
  CONCLUSIONS
  Under physiological conditions the 3.7-kb rocG transcript may be tightly controlled by a roadblock mechanism involving P-Ser-HPr/CcpA in 168 cells, while in 1A95 cells abolished repression of the 3.7-kb transcript. Accumulation of DegU-P in 1A95 affects central carbon metabolism involving lctE enhanced by unknown mechanisms, downregulates FBP levels earlier, and inactivates HPrK to allow the 3.7-kb transcription, and thus similar events may occur in other catabolite repressive loci.
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan. ktanaka@people.kobe-u.ac.jp.
authors.forename: Kosei
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Agrobioscience, Kobe University, Kobe, Hyogo, Japan. kana_smileday_o53o@yahoo.co.jp.
authors.forename: Kana
authors.initials: K
authors.lastname: Iwasaki
authors.affiliation: Biological Science Laboratories, Kao Corporation, Haga, Tochigi, Japan. morimoto.takuya@kao.co.jp.|Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan. morimoto.takuya@kao.co.jp.
authors.forename: Takuya
authors.initials: T
authors.lastname: Morimoto
authors.affiliation: Department of Agrobioscience, Kobe University, Kobe, Hyogo, Japan. takatugu_m_8@yahoo.co.jp.
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Matsuse
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan. hasunuma@port.kobe-u.ac.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hasunuma
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan. stakenaka@people.kobe-u.ac.jp.|Department of Agrobioscience, Kobe University, Kobe, Hyogo, Japan. stakenaka@people.kobe-u.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takenaka
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan. c-onuma@bs.naist.jp.
authors.forename: Onuma
authors.initials: O
authors.lastname: Chumsakul
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan. shu@bs.naist.jp.
authors.forename: Shu
authors.initials: S
authors.lastname: Ishikawa
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan. nogasawa@bs.naist.jp.
authors.forename: Naotake
authors.initials: N
authors.lastname: Ogasawara
authors.affiliation: Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo, Japan. kenyoshi@kobe-u.ac.jp.|Department of Agrobioscience, Kobe University, Kobe, Hyogo, Japan. kenyoshi@kobe-u.ac.jp.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002244:Carbon / Q000378:metabolism; D057465:Catabolite Repression / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D056426:Genetic Loci; D005969:Glutamate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009876:Operon; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C066497:DegU protein, Bacteria; D012333:RNA, Messenger; D002244:Carbon; D007770:L-Lactate Dehydrogenase; D005969:Glutamate Dehydrogenase