title: Identification of regulatory motifs in the CHO genome for stable monoclonal antibody production.
abstract: Chinese hamster ovary (CHO) cell lines are widely used for therapeutic protein production. When a transgene is integrated into the genome of a CHO cell, the expression level is highly dependent on the site of integration because of positional effects such as gene silencing. To overcome negative positional effects and establish stable CHO cell lines with high productivity, several regulatory DNA elements are used in vector construction. Previously, we established the CHO DR1000L-4N cell line, a stable and high copy number Dhfr gene-amplified cell line. It was hypothesized that the chromosomal location of the exogenous gene-amplified region in the CHO DR1000L-4N genome contains regulatory motifs for stable protein production. Therefore, we isolated DNA regulatory motifs from the CHO DR1000L-4N cell line and determined whether these motifs act as an insulator. Our results suggest that stable expression of a transgene can be promoted by the CHO genome sequence, and it would be a powerful tool for therapeutic protein manufacturing.
authors.affiliation: Institute of Bioscience and Bioindustry, Tokushima University, 2-1 Minamijosanjima-cho, Tokushima, 770-8506, Japan.|Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.|Biotechnology Laboratories, Astellas Pharma Inc., 5-2-3 Tokodai, Tsukuba-shi, Ibaraki, 300-2698, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takagi
authors.affiliation: TOYOBO Co.Ltd., 10-24 Toyo-cho, Tsuruga, Fukui, 914-8550, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: TOYOBO Co.Ltd., 10-24 Toyo-cho, Tsuruga, Fukui, 914-8550, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Masuda
authors.affiliation: TOYOBO Co.Ltd., 10-24 Toyo-cho, Tsuruga, Fukui, 914-8550, Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Nishii
authors.affiliation: TOYOBO Co.Ltd., 10-24 Toyo-cho, Tsuruga, Fukui, 914-8550, Japan.
authors.forename: Bunsei
authors.initials: B
authors.lastname: Kawakami
authors.affiliation: Institute of Bioscience and Bioindustry, Tokushima University, 2-1 Minamijosanjima-cho, Tokushima, 770-8506, Japan. omasa@bio.eng.osaka-u.ac.jp.|Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan. omasa@bio.eng.osaka-u.ac.jp.
authors.forename: Takeshi
authors.identifier: http://orcid.org/0000-0003-0635-3862
authors.initials: T
authors.lastname: Omasa
keywords: Chinese hamster ovary cells; Epigenetics; Insulator; Therapeutic antibody