title: Impact of Different Promoters on Episomal Vectors Harbouring Characteristic Motifs of Matrix Attachment Regions.
abstract: We previously demonstrated that the characteristic sequence of matrix attachment regions (MARs) allows transgenes to be maintained episomally in CHO cells. In the present study, six commonly used promoters from human cytomegalovirus major immediate-early (CMV), simian vacuolating virus 40 (SV40), Rous sarcoma virus, Homo sapiens ubiquitin C, phosphoglycerate kinase, and β-globin, respectively, were evaluated to determine their effects on transgene expression and stability in CHO cells stably transfected via the episomal vector harbouring characteristic MAR motifs. The CHO cells were transfected with vectors and then screened using G418, after which the stably transfected cells were split into two and further cultured either in the presence or absence of G418. Of the six promoters, the CMV promoter yielded the highest transgene expression levels and the highest transfection efficiency, whereas the SV40 promoter maintained transgene expression more stably during long-term culture than the other promoters did. The CMV and SV40 promoter-containing vectors were furthermore episomally maintained and conferred sustained eGFP expression in the cells even under nonselective conditions. On the basis of these findings, we conclude that the CMV promoter performs best in terms of yielding both high expression levels and high levels of stability using this episomal vector system.
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Xiao-Yin
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Jun-He
authors.initials: JH
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Qiu-Li
authors.initials: QL
authors.lastname: Sun
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Chun-Peng
authors.initials: CP
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.
authors.forename: Tian-Yun
authors.initials: TY
authors.lastname: Wang