毛竹LTR反转录转座子PHRE6的克隆与转录活性分析

Phyllostachys edulis LTR Transposon-Cloning and Transcriptional Activity Identification of PHRE6

长末端重复序列(long terminal repeat,LTR)反转录转座子是真核生物基因组中普遍存在的一类可移动的DNA序列,因两端具有长末端重复序列而得名。大多数LTR反转录转座子能够感受外界环境的变化,具有转录激活特性和转座激活特性。该研究从毛竹(Phyllostachys edulis,Ph.edulis)基因组中克隆出一条完整的LTR反转录转座子,命名为PHRE6(Phyllostachys edulisretrotransposons 6),该转座子全长为5 620 bp,具有GAG和POL保守结构域。通过荧光定量PCR检测了PHRE6在DNA甲基化抑制剂和不同胁迫处理(包括辐照、高温、低温、高盐)的毛竹实生苗中转录水平的变化,结果表明,在DNA甲基化抑制剂处理后和高温(42°C)、低温(16°C、4°C)、高盐(100 mmol/L、200 mmol/L、300 mmol/L NaCl溶液)胁迫处理下PHRE6表达水平均有显著提高。以上结果说明,PHRE6是一个具有转录活性的反转录转座子,可能参与毛竹逆境响应过程。

Long terminal repeats（LTR） retrotransposons are a type of mobile DNA sequence that is commonly found in eukaryotic genomes and are named after having long terminal repeats at both ends. Most LTR retrotransposons are able to sense changes in the external environment, with transcriptional activation and transposition activation properties. In this study, a complete LTR retrotransposon is cloned from the genome of Phyllostachys edulis（Ph. edulis）, named PHRE6（Phyllostachys edulis retrotransposons 6）. The total length of the transposon is 5 620 bp which has GAG and POL conserved domains. The transcriptional changes of PHRE6 in DNA methylation inhibitors and the treatment of different stress treatments（including radiation, high temperature, low temperature and high salt） in Phyllostachys edulis seedlings are detected by Real-time fluorescence quantitative PCR and after DNA methylation inhibitor treatment. High temperature（42 °C）, low temperature（16°C, 4 °C）, high salt（100 mmol/L, 200 mmol/L, 300 mmol/L NaCl solution） stress levels significantly increase the expression level. This result indicates that PHRE6 is a transcriptionally active retrotransposon and may be involved in the response process of Ph. edulis.