Base editing-mediated exon-specific knockout of glutamine synthetase generates a high-productivity CHO cell line for antibody manufacturing.
- 1State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
- 2Shanghai OPM Biosciences Co. Ltd, Shanghai, 201321, China.
- 3State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China. [email protected].
Abstract
The Chinese hamster ovary (CHO) cell platform dominates recombinant protein production, with the glutamine synthetase (GS) system widely used for clonal selection. However, we observed variable performance between two commercial CHO lines (ATCC CHO-K1 and CHOZN®), which carry distinct intragenic GS deletions and differential residual transcript levels, raising the possibility that the premature termination codon (PTC) position contributes to this phenotypic divergence. To systematically assess the impact of the PTC position, we used base editing to introduce PTCs into each of the six coding exons of Glul. Among the resulting clonal lines, the exon 7-edited (E7) variant exhibited complete GS ablation and sustained high viability. In fed-batch production of an anti-PD-1 monoclonal antibody, E7 achieved higher titers and specific productivities than CHOZN®, with sustained viability. Our findings demonstrate that PTC location is a key determinant of GS knockout completeness and cellular phenotype, identifying exon 7 as a critical knockout target that offers a defined, exon-resolved strategy for accelerating CHO cell line development and improving recombinant protein titers.
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BibTeX
@article{pu2026base,
title = {{Base editing-mediated exon-specific knockout of glutamine synthetase generates a high-productivity CHO cell line for antibody manufacturing.}},
author = {Tianting Pu and Chengcheng Wang and Hui Lou and Ye Mi and Saiyi Zhang and Siyu Liu and Zhihua Xiao and Qiyao Wang and Qin Liu and Yajing Liu},
journal = {Bioresources and bioprocessing},
year = {2026},
month = oct,
doi = {10.1186/s40643-026-01150-0},
url = {https://europepmc.org/article/MED/42909796},
note = {CC BY},
}
RIS
TY - JOUR
TI - Base editing-mediated exon-specific knockout of glutamine synthetase generates a high-productivity CHO cell line for antibody manufacturing.
AU - Tianting Pu
AU - Chengcheng Wang
AU - Hui Lou
AU - Ye Mi
AU - Saiyi Zhang
AU - Siyu Liu
AU - Zhihua Xiao
AU - Qiyao Wang
AU - Qin Liu
AU - Yajing Liu
PY - 2026
DA - 2026/10/23
JO - Bioresources and bioprocessing
DO - 10.1186/s40643-026-01150-0
UR - https://europepmc.org/article/MED/42909796
AB - The Chinese hamster ovary (CHO) cell platform dominates recombinant protein production, with the glutamine synthetase (GS) system widely used for clonal selection. However, we observed variable performance between two commercial CHO lines (ATCC CHO-K1 and CHOZN®), which carry distinct intragenic GS deletions and differential residual transcript levels, raising the possibility that the premature termination codon (PTC) position contributes to this phenotypic divergence. To systematically assess the impact of the PTC position, we used base editing to introduce PTCs into each of the six coding exons of Glul. Among the resulting clonal lines, the exon 7-edited (E7) variant exhibited complete GS ablation and sustained high viability. In fed-batch production of an anti-PD-1 monoclonal antibody, E7 achieved higher titers and specific productivities than CHOZN®, with sustained viability. Our findings demonstrate that PTC location is a key determinant of GS knockout completeness and cellular phenotype, identifying exon 7 as a critical knockout target that offers a defined, exon-resolved strategy for accelerating CHO cell line development and improving recombinant protein titers.
SN - 2197-4365
ER -