Liu B, Wendel J F
Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
Genome. 2000 Oct;43(5):874-80.
Plant retrotransposons are largely inactive during normal development, but may be activated by stresses. Both copia-like and gypsy-like retrotransposons of rice were activated by introgression of DNA from the wild species Zizania latifolia Griseb. The copy number increase was associated with cytosine methylation changes of the elements. Activity of the elements was ephemeral, as evidenced by nearly identical genomic Southern hybridization patterns among randomly chosen individuals both within and between generations for a given line, and the absence of transcripts based on Northern analysis. DNA hypermethylation, internal sequence deletion, and possibly other mechanisms are likely responsible for the rapid element repression. Implications of the retroelement dynamics on plant genome evolution are discussed.
植物逆转录转座子在正常发育过程中大多处于不活跃状态，但可能会因胁迫而被激活。通过导入野生种菰（Zizania latifolia Griseb.）的DNA，水稻中类copia和类gypsy逆转录转座子均被激活。拷贝数的增加与这些元件的胞嘧啶甲基化变化有关。这些元件的活性是短暂的，这一点从给定株系内和不同世代间随机选择的个体具有几乎相同的基因组Southern杂交模式以及Northern分析未检测到转录本可以得到证明。DNA超甲基化、内部序列缺失以及可能的其他机制可能是导致这些元件迅速受到抑制的原因。本文讨论了逆转录元件动态变化对植物基因组进化的影响。
