短额负蝗线粒体基因组及其lrRNA和srRNA二级结构分析

Complete Mitochondrial Genome and Secondary Structures of lrRNA and srRNA of Atractomorpha sinensis (Orthoptera, Pyrgomorphidae)

采用长距PCR扩增及保守引物步移法测定并注释了短额负蝗的线粒体基因组全序列。结果表明,短额负蝗的线粒体基因组全长15558bp,A+T含量为74.3%,37个基因位置与飞蝗的一致,基因间隔序列共计11处64bp,间隔长度从1～16bp不等;有15对基因间存在51bp重叠,重叠碱基数在1～8bp之间。13个蛋白质编码基因中找到6种可能的起始密码子,有12个基因在基因3'端能找到完全的TAA或TAG终止密码子,只有ND5基因终止密码子为不完整的TA。除tRNASer(AGN)外,其余21个tRNA基因的二级结构均属典型的三叶草结构。tRNASer(AGN)的DHU臂缺失,在相应的位置上只形成一个环。预测的lrRNA二级结构总共有6个结构域(结构域Ⅲ缺失),49个茎环结构。预测的srRNA的二级结构包含3个结构域,33个茎环结构。A+T丰富区中存在一个被认为与复制及转录起始有关的Ploy(T)(T-stretch)结构。

The complete sequence of Atractomorpha sinensis mitochondrial genome was determined using long PCR and conserved primer walking approaches. The results showed that the entire mitochondrial genome ofA. sinensis is 15 558 bp long with A＋T content 74.3 %. All 37 genes are conserved in the position observed in that of Locusta migratoria, Genes are closely assembled one after the other, leaving a total of 64 bp （excluding the A＋T rich region） in intergenic spacers, ranging in size from 1 bp to 16 bp. The extremities of some genes overlap with each other by a few nucleotides, of which 15 overlaps range in size from lbp to 8 bp, giving a total of 51 overlapping nucleotides. In the 13 protein coding genes （PCGs）, six types of start codons were identified, in which TAA and TAG were used in 12 PCGs as stop codons, except ND5 （TA）. Most tRNA genes could form typical secondary structures except tRNA^Ser （AGN）, which had an absence of the DHU arm. There are six domains, 49 helices and three domains, 33 helices in the secondary structures of IrRNA and srRNA, respectively. In addition, there is an A＋T rich region with 778 bp in length containing a polythyrnidine stretch that may be involved in replication and/or translation initiation.