Ubiquitous chromatin opening element enhance Darbepoetin alfa expression in CHO DG44 cell line

Abstract

Despite extensive efforts in biotherapeutics production, there is a pressing need to enhance the biomanufacturing process to meet the growing demand for recombinant products. Ubiquitous Chromatin Opening Element (UCOE), chromatin-modifying elements derived from CpG islands, are crucial in regulating gene expression. Therefore, to explore the UCOE effect on gene expression, we cloned codon-optimized Darbepoetin alfa (DPO) sequence into the pOptiVEC then the Darbepoetin alfa-IRES-DHFR fragment was digested, and cloned into the UCOE vector. Both pOptiVEC-DPO and UCOE-DPO-IRES-DHFR cassettes were linearized and transfected into the two cell pools of CHO DG44 cells. The transfected cells were adapted with CD OptiCHO™ medium after 20 days. Recombinant DPO expression was evaluated by qRT-PCR technique. Qualitative and quantitative protein expression analysis was also carried out by western blotting and ELISA assays. Our findings showed a boosted DPO expression rate at both mRNA and protein levels in the UCOE-DPO-IRES-DHFR pool compared to pOptiVEC-DPO. These data suggest that UCOE and codon optimization result in high and stable gene expression in the CHO DG44 cell line.