兴安落叶松Ty1-copia型逆转座子逆转录酶序列的克隆及生物信息学分析

Cloning and Bioinformatic Analysis of Reverse Transcriptases of Ty1-copialike Retrotransposons from Larix gmelinii

为深入了解兴安落叶松的基因组构成及其逆转座子基因的特征,本研究克隆了其逆转座子逆转录酶序列,并进行了生物信息学分析。根据Tyl-copia型逆转座子逆转录酶的保守序列设计简并引物,并利用PCR技术获得了26条逆转座子逆转录酶序列。这些序列去除引物后的核苷酸长度范围为237~251 bp,序列间相似度为55.9%~90.9%,可被分为6个家族。氨基酸预测结果显示,有3条序列存在移框突变,9条序列存在终止密码子突变。系统进化分析显示,所克隆的17条没有发生终止密码子突变的序列分别与处于不同进化阶段的其他植物的Tyl-copia型逆转录酶具有共同的起源。研究结果证实兴安落叶松含有类型丰富的Tyl-copia型逆转座子,可为该物种逆转座子基因资源的开发和利用提供依据。

For further understanding genome composition and diversity of retrotransposons of Larix gmelinii, 26 of reverse transcriptases, referred to as Lg CRE1~Lg CRE26, were isolated using genomic-PCR with the degenerate primers in conserved domains of reverse transposases in Tyl-copia-like retrotransposons. The isolated nucleotide sequences excluding primers varied from 237~251 bp, which consisted of six families, and homology ranged from55.9%~90.9%. The deduction of amino acids by DNAMAN revealed that the frameshift mutation and terminator mutation exist in three and nine sequences, respectively. Phylogenetic analysis showed that the Lg CREs have same origin to Tyl-copia retrotransposon transposases from the other plants in different evolution stages. These results confirmed the presence of various Tyl-copia-like retrotransposons in the genome of L. gmelinii, and may provide valuable information for exploitation and application of the retrotransposons in the larch species.