[The cloning and expression of the beta-galactosidase gene of Candida pseudotropicalis yeasts in Escherichia coli cells]

Abstract

The gene encoding the beta-galactosidase of the yeast Candida pseudotropicalis was cloned on YEp13 shuttle vector as the XhoI-fragment of chromosomal DNA of about 9.5 kb. SalGI-fragment of 7.5 kb with the beta-galactosidase gene was subcloned from the pG2 hybrid plasmid obtained into the pBR322 plasmid and then shortened to give 5.2 kb via deletion on XhoI site. This plasmid constructed was designated pBG2-1. In DNA/DNA hybridization studies the appearance of one XhoI-fragment and seven EcoRI-fragments in DNA C. pseudotropicalis hybridized to the DNA cloned fragment and the absence of hybridization to DNA Escherichia coli were shown. The beta-galactosidase activity of cells of transformants of E. coli was lower than the activity of prototrophic strain. The beta-galactosidase biosynthesis in transformants was insignificantly induced by lactose and IPTG and was not repressed by glucose.