Improved antibody production in Chinese hamster ovary cells by ATF4 overexpression.

To improve antibody production in Chinese hamster ovary (CHO) cells, the humanized antibody-producing CHO DP-12-SF cell line was transfected with the gene encoding activating transcription factor 4 (ATF4), a central factor in the unfolded protein response. Overexpression of ATF4 significantly enhanced the production of antibody in the CHO DP-12-SF cell line. The specific IgG production rate of in the ATF4-overexpressing CHO-ATF4-16 cells was approximately 2.

Overexpression of GADD34 enhances production of recombinant human antithrombin III in Chinese hamster ovary cells.

To improve the production of recombinant human antithrombin III (AT-III) in Chinese hamster ovary (CHO) cells, the gene encoding growth arrest and DNA damage inducible protein 34 (GADD34), which is a transcription factor involved in the unfolded protein response (UPR), was cloned from CHO-K1 cells. Overexpression of GADD34 significantly enhanced the production of recombinant AT-III in CHO 13D-35D cells. The specific rate of AT-III production in the GADD34-overexpressing CHO 13D-35D cells reached approximately 28 pg/cell/d.

Improved production of recombinant human antithrombin III in Chinese hamster ovary cells by ATF4 overexpression.

To improve the production of recombinant human antithrombin III (AT-III) in Chinese hamster ovary (CHO) cells, the genes encoding transcription factors, ATF4 (activating transcription factor 4) and XBP-1s (the spliced form of X-box binding protein 1), which were involved in the mammalian unfolded protein response (UPR), were cloned from CHO-K1 cells. Overexpression of ATF4 significantly enhanced the production of recombinant AT-III in CHO 13D-35D cells. The specific rate of AT-III production in the ATF4-overexpressed CHO 13D-35D cells reached approximately 23 pg/cell/day.

Production of recombinant human antithrombin by Pichia pastoris.

This paper deals with the production of recombinant human antithrombin (rAT) by the methylotrophic yeast Pichia pastoris. In preliminary methanol-limited fed-batch fermentation, the rAT concentration reached 324 mg/l at 192 h of cultivation, but the specific heparin cofactor (HC) activity of rAT in the culture supernatant was 10% of that of plasma-derived antithrombin (pAT). To improve the specific HC activity of rAT, effort was first focused on the optimization of culture pH and media composition, resulting in protection of rAT against pH-dependent instability and proteolytic degradation.

High-level production of prourokinase-annexin V chimeras in the methylotrophic yeast Pichia pastoris.

Prourokinase (proUK)-annexin V chimeras expressed by the methylotrophic yeast Pichia pastoris in a synthetic medium as part of a system designed to yield a novel thrombolytic agent are degraded, as it is thought, by various yeast proteases present in the culture supernatant. Minimization of proteolysis was therefore investigated to increase the yield of intact proUK-annexin V. Protease inhibitor screening study indicated several proteases including at least serine protease like chymotrypsin were involved in the proteolysis.

Optimization of human serum albumin production in methylotrophic yeast Pichia pastoris by repeated fed-batch fermentation.

An optimization method for repeated fed-batch fermentation was established with the aim of improving the recombinant human serum albumin (rHSA) production in Pichia pastoris. A simulation model for fed-batch fermentation was formulated and the optimal methanol-feeding policy calculated by dynamic programming method using five different methanol-feeding periods. The necessary state variables were collected from the calculated results and used for further optimization of repeated fed-batch fermentation.