中文摘要：

目的：克隆SRG基因、原核表达并鉴定。方法：从培养的人骨肉瘤细胞SOSP-9607中提取总RNA，经RT—PCR获得SRG基因。将该基因克隆到pGEM—T—Easy克隆载体中，测序、鉴定。将测序正确的SRG基因亚克隆到pET-28（a^＋）表达载体中，构建SRG表达载体，IPTG诱导表达2h～6h，做SDS—PAGE分析，鉴定SRG蛋白的表达。结果：DNA测序证明，获得了SRG基因，其序列与GenBank中报道序列完全一致。SDS—PAGE分析表明，SRG蛋白获得高效表达，其相对分子质量为22kDa，表达量约占菌体总蛋白的25％。结论：SRG基因的克隆和表达均获得了成功，为进一步探讨SRG基因在骨肉瘤诊治中应用奠定了基础。

英文摘要：

Objective： To clone, express and identify human SRG gene, Methods：Total RNA was extracted from human osteosarcoma cells and the full length cDNA of SRG was obtained by RT - PCR. The SRG gene was cloned into pGEM - T - Easy vector and sequenced. Then the gene was inserted to BamHI and Sal I site of pET - 28 （ a ＋ ） expression vector to construct the expression vector which was transformed into E. coil BL21. After the transformed bacteria were induced at IPTG for 2 - 6h the expressed protein was analyzed by SDS - PAGE. Results： DNA sequencing results showed that SRG gene was exactly consistent with the sequence reported in GenBank. SDS - PAGE analysis demonstrated that SRG protein was expressed in E. coli and the relative molecular mass of it was 22 kDa. The protein band amounted to 25% of total bacteria total protein. Condusions：The results show that SRG gene has been successfully cloned and expressed. It lays a foundation for further studies of the applications of SRG in the osteosarcoma diagnosis and therapy.