摘要: 运用RT-PCR方法, 从白鹅脑垂体总RNA中扩增得到了催乳素(Prolactin, PRL)基因编码区序列cDNA, 并将其克隆到pMD18-T载体上。DNA序列分析表明, PRL cDNA包括终止密码子在内的长度为690 bp，编码230个氨基酸残基的蛋白质, 与皖西白鹅的有所差异, 二者碱基同源性在99.57%, 氨基酸同源性达99.56%。将PRL基因编码区序列cDNA定向克隆到表达载体pET-32a (+)中, 构建表达质粒pET-32a(+)-PRL。该质粒的BL21 (DE3)转化菌在IPTG的诱导下可表达PRL基因融合蛋白, IPTG终浓度1 mmol/L, 37℃, 诱导4 h表达量最高, 表达量约占菌体总蛋白的28.96%。

Abstract: The mature segment gene of prolactin (PRL) in White Goose was amplified from pituitary by RT-PCR and then cloned into the pMD18-T vector. Sequencing analysis showed that the cDNA has a length of 690 bp including the termina-tion codon and encodes a protein composed of 230 amino acids, which differs from the published PRL cDNA sequence. There is a homology of 99.57% in base and 99.56% in amino acids with that of Wanxi White Goose, respectively. A pro-karyotic expression vector, pET-32a(+), was used to construct the recombinant plasmid pET-32a(+)-PRL to produce protein. Having been induced by IPTG，the host cell carrying the recombinant plasmid expressed the recombinant PRL. The opti-mal condition for expression is 1 mmol/L IPTG at 37℃. Based on this condition, the expression rose to the highest level by 4 h of induction, accounting for 28.96% of the total bacterial protein.