甜樱桃(Prunus avium)PaGAST基因的电子克隆及生物信息学分析

为获得甜樱桃PaGAST 基因的cDNA 序列，并预测该基因编码蛋白的结构与功能，以草莓FaGAST1 基因序列为探针，通过基于NCBI数据库中表达序列标签的电子克隆技术对甜樱桃PaGAST 基 因进行克隆。利用生物信息学方法对其编码蛋白的理化性质、疏水性和亲水性、信号肽序列、跨膜结构域、亚细胞定位及功能等方面进行分析。结果表明：甜樱桃PaGAST 基因长度为750 bp，开放阅读框长度为324 bp，编码107 个氨基酸，N末端存在信号肽序列，C末端含有保守的GASA结构域。由于PaGAST蛋白中含有的疏水性氨基酸残基较多，该蛋白具有跨膜螺旋区，是一种跨膜蛋白，且有10 个预测的蛋白激酶磷酸化位点。亚细胞定位分析表明，PaGAST蛋白分布在细胞膜外的可能性很大。功能预测显示，PaGAST 基因可能具有响应胁迫应答、信号转导和免疫应答方面的功能。进化分析显示甜樱桃PaGAST蛋白与桃的亲缘关系最近。在一定程度上为甜樱桃PaGAST 基因的克隆及功能鉴定奠定理论基础。

Electronic Cloning and Bioinformatics Analysis of PaGAST Gene in Sweet Cherry (Prunus avium)

To obtain the cDNA sequence of sweet cherry PaGAST gene and predict the structure and functions of the corresponding protein, PaGAST gene was cloned by electronic cloning technology based on EST sequences from NCBI databases using strawberry FaGAST1 gene sequence as a probe. The bioinformatics methods were utilized to analyze the physical and chemical properties, hydrophobicity and hydrophilicity, signal peptide sequence, transmembrane domain, subcellular localization, functions and other relevant characteristics of the corresponding protein. The results showed that sweet cherry PaGAST gene was 750 bp in length, and its open reading frame was 324 bp long, encoding a polypeptide of 107 amino acids with a signal peptide sequence in the N-terminal and a conserved GASA domain in the C-terminal. Because of high content of hydrophobic amino acid residues among peptide sequences, the PaGAST protein contained a transmembrane helical region, which meant it was a transmembrane protein with 10 presumed protein kinase phosphorylation sites. Subcellular localization analysis showed that the PaGAST protein was very likely to be localized outside the cell membrane. Functional prediction revealed that PaGAST gene had the greatest probability in participation of stress response, signal transduction and immune response. Phylogenetic analysis indicated that sweet cherry PaGAST protein was most closely related to peach. The results above lay a theoretical foundation for the cloning and functional identification of sweet cherry PaGAST gene to some extent.