title: A new Bacillus cereus DNA-binding protein, HlyIIR, negatively regulates expression of B. cereus haemolysin II.
abstract: Haemolysin II, HlyII, is one of several cytotoxic proteins produced by Bacillus cereus, an opportunistic human pathogen that causes food poisoning. The hlyII gene confers haemolytic activity to Escherichia coli cells. Here a new B. cereus gene, hlyIIR, which is located immediately downstream of hlyII and regulates hlyII expression, is reported. The deduced amino acid sequence of HlyIIR is similar to prokaryotic DNA-binding transcriptional regulators of the TetR/AcrA family. Measurements of haemolytic activity levels and of hlyII promoter activity levels using gene fusions and primer-extension assays demonstrated that, in E. coli, hlyII transcription decreased in the presence of hlyIIR. Recombinant HlyIIR binds to a 22 bp inverted DNA repeat centred 48 bp upstream of the hlyII promoter transcription initiation point. In vitro transcription studies showed that HlyIIR inhibits transcription from the hlyII promoter by binding to the 22 bp repeat and RNA polymerase, and by decreasing the formation of the catalytically competent open promoter complex.
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Zhanna I
authors.initials: ZI
authors.lastname: Budarina
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Nikitin
authors.affiliation: Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Zenkin
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Marina
authors.initials: M
authors.lastname: Zakharova
authors.affiliation: Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Semenova
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlyapnikov
authors.affiliation: Pushchino State University, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Ekaterina A
authors.initials: EA
authors.lastname: Rodikova
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Masyukova
authors.affiliation: Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Ogarkov
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Gleb E
authors.initials: GE
authors.lastname: Baida
authors.affiliation: The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Solonin
authors.affiliation: Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Severinov
mesh_terms: D019677:Artificial Gene Fusion; D001409:Bacillus cereus / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000633:toxicity; D004268:DNA-Binding Proteins / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006460:Hemolysin Proteins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012091:Repetitive Sequences, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D037521:Virulence Factors / Q000235:genetics; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: C085361:ApxII toxin, bacteria; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D006460:Hemolysin Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D014157:Transcription Factors; D037521:Virulence Factors; D012321:DNA-Directed RNA Polymerases; D001616:beta-Galactosidase