小菜蛾鱼尼丁受体基因克隆及序列分析

Molecular cloning and sequence analysis of ryanodine receptor gene in the diamondback moth,Plutella xylostella

利用RT-PCR和RACE技术克隆了小菜蛾(Plutella xylostella)鱼尼丁受体(Px-RyR)基因,其核苷酸序列全长15 748bp,5′非编码区267bp,3′端非编码区109bp,开放阅读区全长为15 372bp(GenBank登录号:JF927788),编码5 123个氨基酸残基。估测其蛋白分子量为579.39ku,等电点为5.45。该基因编码氨基酸序列和其他鳞翅目昆虫RyR氨基酸序列比对相似性较高(92%),与哺乳动物3种亚型RyRs的相似性为45%～47%。此外,二级结构预测,其C-末端存在6个跨膜区域;且Px-RyR中存在一个出现4次重复,长度为89～95个氨基酸的RyR结构域,平均相似性为33%。

The full-length cDNA of the ryanodine receptor from the lepidopteran pest Plutella xylostella （Px- RyR） was 15 748 bp, containing a 5＇-UTR of 267 bp, a 3＇-UTR of 109 bp and a full open reading frame （ORF） of 15 372 bp （GenBank accession No. JF927 788）. The amino acid sequence deduced from the sequence was 5 123 a- mino acids. The calculated molecular weight for Px-RyR was 579.39 ku, and its isoelectric point was 5.45. The deduced amino acids sequence of Px-RyR showed a high level of similarity with the RyRs sequences from other Lepidoptera insects, such as the tobacco budworm Heliothis virescens （92%） and silkworm Bombyx mori （92%）. It shared 45%--47% similarity with the vertebrate isoforms. In addition, there were six essential transmembrane （TM） segments, predicted from the secondary structure of the deduced amino acid sequence at C-terminal of Px- RyR. A repeated sequence motif of 89--95 amino acids was observed, sharing 33% similarity on average and oc- curring four times.