title: Limitations in the process of transcription and translation inhibit recombinant human chorionic gonadotropin expression in CHO cells.
abstract: Human chorionic gonadotropin (hCG) is a glycoprotein hormone that exists as a heterodimer with a α subunit and β subunit assembled together with disulfide bridges. This hormone plays an important role in the detection of ovulation induction and in the treatment of certain diseases that cause female infertility. The effects of transcription, subunit expression, assembling and secretion on recombinant hCG expression in CHO cells were studied using stable high-producing and low-producing cell lines generated by the FLP-In™ system. The results indicated that the mRNA and polypeptide levels of the β subunit were always higher than those of the α subunit. Further study confirmed that the differences were caused by the transcription rate rather than by mRNA stability. In the high-producing cell lines, there was obvious transcription level limitation of the α subunit in contrast to the β subunit. In addition, there was obvious limitation of the synthetic steps from mRNA to polypeptide for both the α subunit and the β subunit, especially the β subunit. Significant limitations of the assembly and secretion levels were not observed in this research. This study presents a research methodology for double subunit protein expression and provides valuable evidence for the enhancement of recombinant hCG productivity.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China(1).
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China(1). Electronic address: xpyi@ecust.edu.cn.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China(1).
authors.forename: Yingping
authors.initials: Y
authors.lastname: Zhuang
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China(1).
authors.forename: Siliang
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001709:Biotechnology; D016466:CHO Cells; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D017931:DNA Primers / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D014176:Protein Biosynthesis / Q000502:physiology*; D021122:Protein Subunits / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D006063:Chorionic Gonadotropin; D017931:DNA Primers; D021122:Protein Subunits; D011994:Recombinant Proteins
keywords: Mammalian cell culture; Recombinant protein; Transcription limitation