title: Positional effects of the matrix attachment region on  transgene expression in stably transfected CHO cells.
abstract: Previous work has shown that the MAR (matrix attachment region) could increase transgene expression in stably transfected CHO (Chinese-hamster ovary) cells. To study the positional effect of MAR on transgene expression, three expression vectors were constructed which contained the human beta-globin MAR in different sites, including the vector with two MARs flanking the CAT (chloramphenicol acetyltransferase) expression cassette, one MAR at the 59 or 39 site. These vectors were transfected into CHO cells. The level of CAT gene expression was most effectively increased by two MARs flanking the CAT expression cassette. This increase was also seen when MAR was inserted at the 59 site upstream of the expression cassette, whereas the transgene expression level decreased when MAR was inserted at the 39 site downstream of the expression cassette. We have also shown that the transgene expression level is not directly proportional to the gene copy number, and gene copy number dependency does not exist.
authors: Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan 453003, People's Republic of China. wty@xxmu.edu.cn
authors: Tian-Yun
authors: TY
authors: Wang
authors: Jun-He
authors: JH
authors: Zhang
authors: Chang-Qin
authors: CQ
authors: Jing
authors: Xian-Jun
authors: XJ
authors: Yang
authors: Jun-Tang
authors: JT
authors: Lin
mesh_terms: D024509:3' Flanking Region; D024506:5' Flanking Region; D000818:Animals; D016466:CHO Cells; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D018628:Gene Dosage; D005786:Gene Expression Regulation; D006801:Humans; D045170:Matrix Attachment Regions / Q000235:genetics*; D010957:Plasmids; D014162:Transfection; D019076:Transgenes; D055544:beta-Globins / Q000235:genetics* / Q000378:metabolism
chemical_list: D055544:beta-Globins; D015500:Chloramphenicol O-Acetyltransferase