Epigenetic regulation of histone methyltransferase SUV39H1 on the expression of recombinant protein in CHO cells.

Histone methylation-mediated epigenetic modification significantly influences gene transcription and expression regulation. This study examined the effects of histone 3 lysine 9 trimethylation (H3K9me3) methyltransferase SUV39H1 and its specific inhibitor chaetocin on recombinant protein expression in Chinese hamster ovary (CHO) cells. Results indicated that stable SUV39H1-knockdown CHO cells exhibited reduced H3K9me3 levels while showing increased expression of recombinant adalimumab (rADM) and human serum albumin (rHSA) by approximately 45% and 136%, respectively. Furthermore, treatment with 20 nM chaetocin, a SUV39H1-specific inhibitor, enhanced expression of enhanced green fluorescent protein (EGFP), rADM, and rHSA in CHO cells. These findings demonstrate that both stable SUV39H1 knockdown and pharmacological inhibition through chaetocin effectively reduce H3K9me3 modification levels in CHO cells while significantly boosting recombinant protein production. The results strongly suggest SUV39H1's critical regulatory role in recombinant protein expression within CHO cell systems. This research establishes a methodological foundation for developing engineered cell lines and optimizing high-efficiency CHO expression systems through cell engineering approaches. KEY POINTS: •SUV39H1 knockdown boosted recombinant protein expression and decreased H3 K9 me3 levels. •Treatment with the SUV39H1-specific inhibitor chaetocin (20 nM) enhanced recombinant protein expression. •It provides a basis for developing efficient epigenetically regulated CHO expression systems.