关键词: 尿激酶原, 大肠杆菌, 稀有密码子, BL21-CodonPlus^TM-RIL, dnaY基因

Abstract: Studies were made on the enhancement of expression of human pro-Urokinase (Pro-UK) cDNA in Eschevichia coli. By means of PCR, the signal peptide DNA sequence was deleted. For study of the limited factors in expression of pro-Urokinase, the pro-UK gene was divided into three fragments, and they were expressed in E.coli BL21(DE3), The expression of middle fragment is very low, because there are several rare codon AGG(Arg) in it. Using a new bacteria E.coli BL21-Codo nPlus^TM-RIL to introduce dnaY gene coding tRNA_agg/aga(Arg) to recognize the rare codon AGG, the expression level of the middle fragment was enhanced to 10%～20% of total cell protein and the expression of the intact pro-UK was enhanced to 5% by more than 10 folds.

Key words: Pro-Urokinase, Eschevichia coli, rare codon, BL21-CodonPlus^TM-RIL, dnaY gene