title: Detailed understanding of enhanced specific productivity in Chinese hamster ovary cells at low culture temperature.
abstract: The specific productivity of tumor necrosis factor receptor-immunoglobulin G1 Fc fusion (TNFR-Fc) (q(TNFR-Fc)) in Chinese hamster ovary (CHO) cells at 30°C was approximately 5-fold higher than that at 37°C. To investigate reasons for increased q(TNFR-Fc) at low culture temperature, TNFR-Fc mRNA levels were determined by real-time PCR. It was found that like q(TNFR-Fc), the relative TNFR-Fc mRNA level was increased by lowering culture temperature, and more importantly, the kinetics of the increase in TNFR-Fc mRNA levels were in accordance with the changes in q(TNFR-Fc). The results demonstrated that the increased transcriptional level of TNFR-Fc was responsible for the increased q(TNFR-Fc) at low culture temperature. Enhanced levels of mRNA could derive from increased gene copy number, improved mRNA stability, or enhanced transcriptional rate. There was not a big change of gene copy number by lowering culture temperature. The transcriptional rate of TNFR-Fc was slightly decreased at 30°C, compared to 37°C. However, mRNA stability of TNFR-Fc was significantly improved by lowering culture temperature. The half-life of TNFR-Fc mRNA was 5.55 h at 30°C, whereas that was 3.69h at 37°C. Taken together, the reasons for the increased q(TNFR-Fc) in CHO cells at low culture temperature were mainly the enhanced TNFR-Fc mRNA levels, which resulted from the improved mRNA stability, rather than the changes in the gene copy number or the transcriptional rate.
authors.affiliation: The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, PR China.
authors.forename: Tian-Ci
authors.initials: TC
authors.lastname: Kou
authors.forename: Li
authors.initials: L
authors.lastname: Fan
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Zhao-Yang
authors.initials: ZY
authors.lastname: Ye
authors.forename: Xu-Ping
authors.initials: XP
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.forename: Wen-Song
authors.initials: WS
authors.lastname: Tan
mesh_terms: D000818:Animals; D016466:CHO Cells; D018929:Cell Culture Techniques / Q000379:methods*; D003080:Cold Temperature; D006224:Cricetinae; D003412:Cricetulus; D000068800:Etanercept; D018628:Gene Dosage; D007074:Immunoglobulin G / Q000096:biosynthesis*; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D007074:Immunoglobulin G; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins; D000068800:Etanercept