Efficient selection of stable chinese hamster ovary (CHO) cell lines for expression of recombinant proteins by using human interferon beta SAR element.
We describe the development of an efficient expression system suitable for the stable expression of recombinant genes in Chinese hamster ovary (CHO) cells using the human interferon beta SAR element. The insertion of two copies of the human interferon beta SAR element at the 5' and 3' flanking regions of the beta-galactosidase reporter gene increased the frequency of beta-galactosidase positive colonies by up to 75% and enhanced beta-galactosidase expression by 15- to 20-fold after G418 selection or 30- to 40-fold at the initial stage of the MTX selection procedure. Deletion analysis showed that the whole DNA regions of the human interferon beta SAR element are required for beta-galactosidase expression enhancement. The developed expression system was also highly effective at enhancing the stable expression of two therapeutically important proteins, namely, erythropoietin (EPO) and hepatocyte growth factor (HGF). We isolated stable colonies with expression levels of 47 microg/10(6) cells/day for EPO and 13 microg/10(6) cells/day for HGF, suggesting that the developed expression system based on the human beta SAR element is suitable for expressing high levels of recombinant proteins in CHO cells.
Kim
Jeong Do
JD
Graduate School of Biotechnology, Kyung Hee University, Yongin City, Kyungki-Do 449-701, Korea.
Yoon
Yeup
Y
Hwang
Hye-Yeon
HY
Park
Jeong Soo
JS
Yu
Sungryul
S
Lee
Jina
J
Baek
Kwanghee
K
Yoon
Jaeseung
J
D000818:Animals; D016466:CHO Cells / Q000145:classification / Q000502:physiology*; D006224:Cricetinae; D003412:Cricetulus; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007370:Interferon Type I / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000096:biosynthesis*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D001616:beta-Galactosidase / Q000096:biosynthesis* / Q000235:genetics*
D007370:Interferon Type I; D011994:Recombinant Proteins; D001616:beta-Galactosidase