Satoh M, Hosoi S, Miyaji H, Itoh S, Sato S
Tokyo Research Laboratories, Kyowa Hakko Co., Ltd., Japan.
Cytotechnology. 1993;13(2):79-88. doi: 10.1007/BF00749934.
Human pro-urokinase (pro-UK) gene was engineered for expression in mammalian cells. The stability of recombinant pro-UKs produced by two kinds of cells, Chinese hamster ovary (CHO) and human lymphoblastoid Namalwa KJM-1 cells, were compared. The pro-UK expressed in CHO cells in serum-free medium was degraded by cysteine endopeptidase secreted by CHO cells. This endopeptidase was inhibited by p-chloromercuribenzonate (PCMB) and leupeptin more efficiently than by aprotinin. On the other hand, the pro-UK expressed in Namalwa KJM-1 cells was not degraded, resulting in the stable production of pro-UK at a rate of 2-3 micrograms/10(6) cells/day by use of a gene amplification method with dihydrofolate reductase (DHFR) in serum-free medium. Thus, Namalwa KJM-1 cells showed the desired characteristics as a host cell for the production of recombinant proteins. The stability of recombinant proteins in heterologous systems may vary depending on the host cells.
人尿激酶原（pro-UK）基因经改造后用于在哺乳动物细胞中表达。比较了两种细胞——中国仓鼠卵巢（CHO）细胞和人淋巴母细胞Namalwa KJM-1细胞产生的重组pro-UK的稳定性。在无血清培养基中CHO细胞表达的pro-UK被CHO细胞分泌的半胱氨酸内肽酶降解。该内肽酶被对氯汞苯甲酸（PCMB）和亮抑酶肽抑制的效率高于被抑肽酶抑制的效率。另一方面，在Namalwa KJM-1细胞中表达的pro-UK未被降解，通过在无血清培养基中使用二氢叶酸还原酶（DHFR）基因扩增方法，以2 - 3微克/10⁶细胞/天的速率稳定产生pro-UK。因此，Namalwa KJM-1细胞作为生产重组蛋白的宿主细胞表现出所需的特性。重组蛋白在异源系统中的稳定性可能因宿主细胞而异。
