원문정보
초록
영어
Protein disulfide isomerase (PDI), an ER-resident molecular chaperone, forms and isomerizes disulfide bonds1. Calnexin (Cnx), also an ER-resident protein interacts with glycoproteins promoting proper folding. The Ca2+ binding property of Cnx links it to apoptosis as Ca2+ signal dissemination from ER generates and mediates apoptosis cascade from the mitochondria2. This study attempts to investigate the effect of PDI and Cnx expression level on specific productivity
(q) and apoptosis of rCHO cells producing thrombopoietin (TPO), antibody (Ab) and TNFR-Fc. Doxycycline-regulated PDI and Cnx expression system in Tet-Off rCHO cells was established. It was found that the q of TPO (qTPO) was unaffected but that of antibody producing cells was increased by 15-27% due to the PDI expression level. The cells with down regulated Cnx showed an increase in the viability by ～20% throughout the batch culture. Western blot
analyses showed a delay in apoptosis. The effect of overexpression of chaperones on q is dependent on the target protein and the chaperone concerned and that calnexin deficiency confers resistance to apoptosis induced by NaBu.