目的:探讨癌蛋白非经典前折叠素RPB5相互作用因子(unconventional prefoldin RPB5 interactor,URI)在胃癌组织中的表达及其临床意义,分析URI对顺铂诱导的胃癌细胞凋亡的影响.方法:采用免疫组化辣根过氧化物酶法检测胃癌组织芯片中URI的表达,并分析其与临床特征的相关性;体外培养胃癌MGC-803细胞和SGC-7901细胞,运用Hiperfect转染试剂分别在两类胃癌细胞株中转染URI siRNA片段构建URI基因敲低细胞株,并用荧光定量PCR和蛋白质印迹法验证敲低效果;将细胞分为空白组、siRNA URI干扰组以及顺铂诱导下的未转染组、无关序列组和siRNA URI干扰组,采用流式细胞术检测各组细胞凋亡情况.结果:胃癌组织芯片检测结果显示,胃癌组织胞质中URI的表达量显著高于癌旁组织(P<0.05),胞核中URI的表达量虽比癌旁组织增高,但无显著性差异.URI的表达量与胃癌患者生存期、临床分期等无显著相关性.URI基因敲低后两类细胞株顺铂诱导的凋亡率均显著增加(P<0.01).结论:URI可能作为一种凋亡抑制因子在胃癌的发生中起作用.

Objective To investigate the properties,structure,isoforms of unconventional prefoldin RPB5 interactor 1(URI1) and its expression in human tissues for further analysis on the functions and regulatory mechanisms of this protein.Methods Multiple webbased analytical tools were used to predict and analyze the structure and properties of URI1 protein.URI1 expressions in multiple human tissues and cells were analyzed by using tissue microarray(TMA) and immunohistochemical(IHC) approaches.Results Based on the NCBI database,URI1 gene encodes a unstable and non-secreted protein containing 535 amino acids in length without notable transmembrane structure.No signal peptide was found at the N-terminus of URI1 protein.UbPred analysis suggested that URI1 contained 11 potential ubiquitination sites among which 6 were highly confident and 5 were moderately confident,and 48 potential phosphorylation sites among which 35 were at serine residues,11 were at threonine and 2 were at tyrosine residues.A glycosylation site was found at the position 287 of amino acid sequence of URI1 and possibly also occurred at the positions of 291 and 371 respectively.No acetylation site was detectable.The predictive alpha-helix accounted for 39.3% of the protein structure.A prefoldin functional domain was found at the N-terminus of URI1 protein.The analysis of TMA and IHC demonstrated that URI1 was ubiquitously but distinctly differentially expressed in multiple human tissues and cells.These results corresponded with the expression spectrum of URI1 mRNA predicted by high density microarray analysis using BioGPS.Conclusion Bioinformatics analysis provided basic structural and functional information of URI1.The characterization of URI1 obtained by using proteomic and genomic approaches may provide novel insights for functional investigation on URI1.