title: Novel Bifidobacterium promoters selected through microarray analysis lead to constitutive high-level gene expression.
abstract: For the development of a food-grade expression system for Bifidobacterium, a strong promoter leading to high-level expression of cloned gene is a prerequisite. For this purpose, a promoter screening host-vector system for Bifidobacterium has been established using β-glucosidase from Bifidobacterium lactis as a reporter and Bifidobacterium bifidum BGN4 as a host, which is β-glucosidase negative strain. Seven putative promoters showing constitutive high-level expression were selected through microarray analysis based on the genome sequence of B. bifidum BGN4. They were cloned into upstream of β-glucosidase gene and transformed into Escherichia coli DH5α and B. bifidum BGN4. Promoter activities were analyzed both in E. coli and B. bifidum BGN4 by measuring β-glucosidase activity. β-Glucosidase activities in all of the transformants showed growth-associated characteristics. Among them, P919 was the strongest in B. bifidum BGN4 and showed maximum activity at 18 h, while P895 was the strongest in E. coli DH5α at 7 h. This study shows that novel strong promoters such as P919 can be used for high-level expression of foreign genes in Bifidobacterium and will be useful for the construction of an efficient food-grade expression system.
authors.affiliation: Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Kim
authors.forename: Myeong Soo
authors.initials: MS
authors.lastname: Park
authors.forename: Geun Eog
authors.initials: GE
authors.lastname: Ji
mesh_terms: D019677:Artificial Gene Fusion; D001644:Bifidobacterium / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D005827:Genetics, Microbial / Q000379:methods; D060847:Metabolic Engineering / Q000379:methods*; D046228:Microarray Analysis / Q000379:methods*; D011401:Promoter Regions, Genetic; D001617:beta-Glucosidase / Q000032:analysis / Q000235:genetics
chemical_list: D001617:beta-Glucosidase