肝再生增强因子的cDNA克隆、表达及表达产物的生物活性研究

以肝部分切除后再生肝组织为起始材料，利用RT-PCR扩增出大鼠肝再生增强因子（ALR），亚克隆于pGEM-T载体，核苷酸序列测定证实为大鼠ALR；将ALRcDNA亚克隆于pBV220质粒，构建了原核表达栽体，并获高效表达菌株，特异表达蛋白占细菌总蛋白的15％，原核表达的ALR在体外缺乏促进大鼠原代培养肝细胞及SMMC-7721肝癌细胞DNA合成的活性，但在体内1／3肝部分切除模型中可刺激肝细胞DNA合成；ALR在生物学活性方面与肝脏刺激物（HSS）存在一定差别，ALR和HSS应是两种不同的活性因子．ALR还具有促肝损伤修复的作用，对其深入研究可能为临床治疗严重肝病提供有效的药物.

Cloning and E-Expression of Rat Augmenter of Liver Regeneration

Various growth factors have been characterized and purified in an attempt to explain the control of liver growth and liver regeneration. Unfortunately,most of the factors so far investigated are not liver specific, and they do not explain liver growth control. A novel liver growth factor found in homogenates of rat liver, termed augmenter of liver regeneration(ALR),was studied.The main results were as follows: 1) Single-strand cDNA was synthesized from rat regeneration liver RNA and the rat ALR cDNA was amplified by PCR, then were subcloned into the pGEM-T vector by TA cloning and Sequence; 2) ALR cDNA were subcloned into the downstream of the P_RP_L promoter of the expression plasmid pBV220, The recombinant plasmids can express stable ALR with high efficiency(up to 15% of the total bacterial soluble proteins) in E. colt DH5α through thermal induction. The expressed recombinant ALRs could not stimulate the 3H-TdR incorporation of primary culture of rat hepatocyte and SMMG-7721 human hepatoma cells in vitro,but it produced a significant increase in the incorporation of 3H-TdR into liver DNA of a 1/3 hepatectomized test animal and also showed a potent antihepatitis effect in vivo.