Centromere-targeted de novo integrations of an LTR retrotransposon of Arabidopsis lyrata.
Centromere-targeted de novo integrations of an LTR retrotransposon of Arabidopsis lyrata.
复制标题
DOI：
10.1101/gad.183871.111
复制
发表时间：
2012-04
影响因子：
10.5
通讯作者：
S. Tsukahara;A. Kawabe;A. Kobayashi;Tasuku Ito;Tomoyuki Aizu;T. Shin-I;A. Toyoda;A. Fujiyama;Y. Tarutani;T. Kakutani
中科院分区：
文献类型：
--
作者：
S. Tsukahara;A. Kawabe;A. Kobayashi;Tasuku Ito;Tomoyuki Aizu;T. Shin-I;A. Toyoda;A. Fujiyama;Y. Tarutani;T. Kakutani
植物基因组随着LTR型反转录转座子的快速增殖而进化，这与它们在基因贫乏区域（例如着丝粒）的聚集积累有关。尽管它们在植物基因组进化中发挥着重要作用，但在植物中尚未发现可靶向整合到基因贫乏区域的可移动 LTR 元件。在这里，我们从头报告了这种有针对性的整合。我们和其他人之前已经证明，当 DNA 甲基化机制受到损害时，拟南芥中的 ATCOPIA93 家族逆转录转座子就会被调动。尽管 ATCOPIA93 家族元件在野生型拟南芥基因组中的拷贝数较低，但在野生型拟南芥基因组中发现了高拷贝数的相关元件，并且它们表现出着丝粒特异性定位。为了直接了解琴叶拟南芥元件聚集积累的机制，我们通过转化将其中一个名为Tal1（拟南芥转座子1）的元件引入拟南芥。引入的Tal1在拟南芥中进行了逆转录转座，并且大多数逆转录拷贝出现在拟南芥的着丝粒重复序列中，表明有针对性的整合。靶向整合尤其令人惊讶，因为琴叶拟南芥和拟南芥之间的着丝粒重复序列显着不同。我们的结果意外地揭示了富含转座子的异染色质区域进化的动态控制。
The plant genome evolves with rapid proliferation of LTR-type retrotransposons, which is associated with their clustered accumulation in gene-poor regions, such as centromeres. Despite their major role for plant genome evolution, no mobile LTR element with targeted integration into gene-poor regions has been identified in plants. Here, we report such targeted integrations de novo. We and others have previously shown that an ATCOPIA93 family retrotransposon in Arabidopsis thaliana is mobilized when the DNA methylation machinery is compromised. Although ATCOPIA93 family elements are low copy number in the wild-type A. thaliana genome, high-copy-number related elements are found in the wild-type Arabidopsis lyrata genome, and they show centromere-specific localization. To understand the mechanisms for the clustered accumulation of the A. lyrata elements directly, we introduced one of them, named Tal1 (Transposon of Arabidopsis lyrata 1), into A. thaliana by transformation. The introduced Tal1 was retrotransposed in A. thaliana, and most of the retrotransposed copies were found in centromeric repeats of A. thaliana, suggesting targeted integration. The targeted integration is especially surprising because the centromeric repeat sequences differ considerably between A. lyrata and A. thaliana. Our results revealed unexpectedly dynamic controls for evolution of the transposon-rich heterochromatic regions.