URI1蛋白生物信息学分析及在人体组织中的表达

Bioinformatics analysis of unconventional prefoldin RPB5 interactor 1 and its expression in human tissues

目的分析人非经典前折叠素RPB5相互作用因子1(URI1)蛋白的特性、结构和变异体,观察URI1蛋白在人组织中的表达。方法通过多种网络分析工具,预测和分析URI1的基本特性及结构。用人组织微阵列免疫组化染色方法检测其在多种组织/细胞中的表达。结果 URI1编码1个535个氨基酸的蛋白质,该蛋白质性质不稳定,无跨膜片段,N末端无信号肽,非分泌型蛋白质,其mRNA在组织中广泛表达。URI1具有11个潜在的泛素化位点,其中6个为高度可信,5个为中度可信。有48个潜在的磷酸化位点(35个在丝氨酸位、11个在苏氨酸位、2个在酪氨酸位)。在第287氨基酸位有一糖基化位点,在第291、371氨基酸位也可能发生糖基化修饰,未发现乙酰化位点。蛋白质结构预测α螺旋(H)占39.63%,N端具有1个PFD功能域。URI1在多种组织/细胞广泛表达并存在明显差异表达,与基于高密度微阵列技术的BioGPS mRNA表达谱数据吻合。结论用生物信息学技术预测了URI1蛋白的结构和功能,为URI1蛋白的相关研究提供了信息。

Objective To investigate the properties, structure, isoforms of unconventional prefoldin RPB5 interaetor 1 （ URI1 ） and its expression in human tissues for further analysis on the functions and regulatory mechanisms of this protein. Methods Multiple web-based analytical tools were used to predict and analyze the structure and properties of URI1 protein. URI1 expressions in multiple hu-man 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 con-tained 11 potential ubiquitination sites among which 6 were highly eoniident and 5 were moderately eonfident, and 48 potential phos-phorylation 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 dif- ferentially expressed in multiple human tissues and ceils. These results corresponded with the expression spectrum of URI1 mRNA pre-dicted 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.