Expression of Helicobacter pylori ggt gene in baculovirus expression system and activity analysis of its products

The gamma-glutamyltranspeptidase (GGT) of Helicobacter pylori (HpGT) is a newly found virulence factor. In an approach to gain insight into the gene function, the four domains of the HpGT were cloned and expressed in baculovirus expression system. The results of a functional assay showed that the HpGT products acted as GGT, even when the N-terminal 380 amino acids were deleted. However, only the full length open reading frame (ORF) of the HpGT gene was apparently effective on cell growth. This result indicated that the products of the full length ORF might have an important role in gastric carcinogenesis. In this paper, we are the first to report that changes of mitochondrial membrane potential can be detected using 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimidazole carbocyanine iodide (JC-1) staining in insect cells.