Molecular Characterization of α-gliadin Genes from Diploid Lophopyrum elongatum and Elymus sibiricus
Molecular Characterization of α-gliadin Genes from Diploid Lophopyrum elongatum and Elymus sibiricus
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发表时间：
2010-01
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通讯作者：
Wei-Dong Wu;Mengzhu Chen;Fanguo Chen;G. Xia
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作者：
Wei-Dong Wu;Mengzhu Chen;Fanguo Chen;G. Xia
从二倍体长穗披碱草和四倍体披碱草中鉴定了6 3个α-醇溶蛋白开放阅读框。序列比较显示，其中约90%含有内部终止密码子或移码。将这些ORF与已报道的α-醇溶蛋白序列进行比对，发现它们编码除聚谷氨酸区外的相同的信号肽结构域、重复结构域和C-末端区域。对重复结构域中前三个密码子的分析发现了两种新的基序类型(GRV和RV)。在第一聚谷氨酸区发现了新类型的基序，包括(Q)3AR(Q)5、(Q)2AR(Q)5、(Q)3A。对小麦中已知的三种类型的乳糜泻(CD)表位进行了筛选，并在重复结构域和C-末端的独特结构域上进行了比较。西伯利亚乳杆菌的一个潜在的真基因(EU016530)含有两种CD表位(Glia-α^2和Glia-α)，而二倍体长穗乳杆菌的真基因(EU018257)则不含Cd表位，只有假基因EU018257含有Glya-α。系统发育分析表明，二倍体长穗麦的α醇溶蛋白与十倍体长穗麦的醇溶蛋白有较高的亲缘关系，而西伯利亚麦醇溶蛋白与其他小麦种的醇溶蛋白有较高的同源性。
Sixty-three α-gliadin open reading frames (ORF) were characterized from diploid Lophopyrum elongatum and tetroploid Elymus sibiricus. Sequence comparison revealed that about 90% of them contained an internal stop codon or frameshift. Alignment between these ORFs and reported α-gliadin sequences reveal that they coded identical signal peptide domain, repetitive domain and C-terminal region, except polyglumatine domains. Analysis of the first three codons in repetitive domains reveals two new types of motifs (GRV and RV). Novel types of motifs, including (Q)3AR(Q)5, (Q)2AR(Q)5, (Q)3A, were characterized in the first polyglumatine region. Three known types of celiac disease (CD) epitopes in Triticum were screened and compared in the repetitive and the C-terminal unique domains. A potential real gene (EU016530) from E. sibiricus contained two types of CD epitode (glia-α^2 and glia-α), whereas, the real genes from diploid L. elongatum are found to contain no CD epitode, only with pseudogenes EU018257 containing glia-α. Phylogenetic analysis showed that α-gliadins from diploid L. elongatum were closely related to those from decaploid L. elongatum, while that from E. sibiricus were more homologous with those from other Triticum species.