Profile of Expression of Helicobacter pylori gamma-glutamyltranspeptidase.
BACKGROUND
Helicobacter pylori produces gamma-glutamyltranspeptidase (GGT), a potential virulence factor involved in induction of host cell apoptosis. Regulation of the production of this protein is not known.


METHODS
The transcription start sites were determined by primer extension analysis. Transcription level of the GGT gene was examined by measuring the mRNA by RT-PCR and expression level of GGT protein was examined by Western blot analysis under different conditions.


RESULTS
Two transcription start sites were identified; thymine at 78-bp upstream and adenine at 79-bp upstream from the ATG codon of the GGT gene. There was a possible -10 consensus promoter sequence (ATTAAT), but no apparent -35 consensus sequence was found. The transcription of the mRNA and the expression of the protein were at almost constant level during the course of culture. The mRNA level increased by exposure to low pH; however, the actual protein expression level remained almost constant. Addition of glutamine or glutamate did not affect the mRNA level and the protein expression level to a remarkable degree, nor did co-culture with AGS cells affect the GGT activity level.


CONCLUSIONS
It was suggested that H. pylori GGT is constitutively expressed under various conditions.
Wachino
Jun-Ichi
J
Department of Bacteriology II, National Institute of Infectious Diseases, Tokyo, Japan.
Shibayama
Keigo
K
Suzuki
Satowa
S
Yamane
Kunikazu
K
Mori
Shigetarou
S
Arakawa
Yoshichika
Y
D001426:Bacterial Proteins / Q000096:biosynthesis*; D015153:Blotting, Western; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016385:TATA Box; D024363:Transcription Initiation Site; D011503:Transglutaminases / Q000096:biosynthesis*; D037521:Virulence Factors / Q000096:biosynthesis
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D037521:Virulence Factors; D011503:Transglutaminases