Application of destabilizing sequences on selection marker for improved recombinant protein productivity in CHO-DG44.
We have developed a systematic and generic way to improve recombinant protein productivities in stable transfections by applying mRNA and protein destabilizing elements to reduce selection marker expression strength. Interferon-gamma (IFNgamma) expression vectors containing different combinations of AU-rich elements (ARE) and mouse ornithine decarboxylase (MODC) PEST region on the amplifiable dihydrofolate reductase (dhfr) selection marker were stably transfected into CHO-DG44 cells. Improvements in specific IFNgamma productivities were 1.7-, 6.6- and 13.3-fold with the application of ARE, MODC PEST, and both ARE and MODC PEST, respectively. To further enhance productivities, compatibility of the destabilizing sequences with methotrexate (MTX) amplification was validated by amplifying the transfected cells to 50nM MTX. A 14- to 27-fold increase in specific IFNgamma productivities were observed after amplification, indicating the compatibility of the two systems. A high specific IFNgamma productivity of 1.05pg/cell/day was also attained by the amplified cell pool with both ARE and MODC PEST.
Ng
Say Kong
SK
Singapore-MIT Alliance, National University of Singapore, 4 Engineering Drive 3, E4-04-10, Singapore 117576, Singapore.
Wang
Daniel I C
DI
Yap
Miranda G S
MG
D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005819:Genetic Markers / Q000235:genetics; D005822:Genetic Vectors; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D020871:RNA Stability / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism
D020413:3' Untranslated Regions; D005819:Genetic Markers; D011994:Recombinant Proteins; D007371:Interferon-gamma; D013762:Tetrahydrofolate Dehydrogenase