目的构建新克隆的肺癌抑瘤基因候选者HLCDG1的融合表达质粒pGEX-6P-1/HLCDG1并在原核表达系统中表达。方法采用多聚酶链式反应(PCR)扩增HLCDG1基因蛋白编码序列,将该片断插入原核表达载体pGEX-6P-1中,转化大肠杆菌BL-21扩增。构建的融合表达质粒经酶切和测序鉴定后,经IPTG诱导表达,SDS-PAGE后考马斯亮蓝染色和W estern b lot鉴定实验结果。结果构建的融合表达质粒酶切和测序鉴定阅读框架正确,导入大肠杆菌中经IPTG诱导出一条分子量约为46kD的新蛋白带,主要存在于细菌沉淀中,W estern b lot鉴定其为GST-HLCDG1融合蛋白。结论HLCDG1基因编码的蛋白质能够在原核细胞中有效表达,为进一步研究该蛋白质的结构和功能奠定研究基础。
HLCDG1, which locates in chromosome 5q33, is a novel gene cloned recently. The HLCDG1 expression was significantly down regulated in the primary lung carcinoma. It was previously studied that HLCDG1 acted like a tumor suppressor gene. In this paper, proteomics studies were performed to analyze the proteomic expression patterns in the HLCDG1-transfected human lung carcinoma cell line (A549-HLCDG1) and in the control vector-transfecred human lung carcinoma cell line (A549-vector). Employing two dimensional gel eleetrophoresis (2DE), the global pattern of protein expressions in A549-HLCDG1 human lung adenocarcinoma cell line expressing stably HL-CDG1 gene were compared with those of control A549-vector cell line to generate a differential protein expression catalog. Forty-two differentially expressed proteins were screened. Thirteen differential proteins were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), which were 6 upregulated (MSH5, MOD, MDH precursor, ETFβ, Prxd Ⅵ and JM23) and 7 downregulated (PLC-δ1, hnRNPA2,hnRNPB1, TIM, TCTP, nm23H-1 and PrxdⅤ) proteins in A549-HLCDG1 cells compared to control A549-vector cells. The above identified proteins were involved in energy metabolism, transcription regulation, antioxidation,cell cycle, metastasis, DNA methylation and mismatch repair. Therefore, these differential expression proteins by HLCDG1 transfection may play some important roles for investigation of the biochemical basis of growth suppression of HLCDG1 gene in lung carcinoma cells A549. Further understanding of this data base may provide valuable resources for the developing novel diagnostic markers and therapeutic targets of lung cancer.
ZOU Fei-yan XIE Hai-long ZENG Ping-yao CHEN Zhu-chu LI Feng XIAO Zhi-qiang FENG Xue-ping ZHANG Peng-fei YANG Hai-yan HU Wei YU Yan-hui OUYANG Yong-mei
