A new Bacillus cereus DNA-binding protein, HlyIIR, negatively regulates expression of B. cereus haemolysin II.
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.
Budarina
Zhanna I
ZI
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Nikitin
Dmitri V
DV
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Zenkin
Nikolay
N
Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
Zakharova
Marina
M
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Semenova
Ekaterina
E
Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
Shlyapnikov
Michael G
MG
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Rodikova
Ekaterina A
EA
Pushchino State University, Nauki Avenue, 5, Pushchino, 142292 Russia.
Masyukova
Svetlana
S
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Ogarkov
Oleg
O
Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
Baida
Gleb E
GE
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Solonin
Alexander S
AS
The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia.
Severinov
Konstantin
K
Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA.
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
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