Analysis of the plant retrotransposon Tto1 and its use for genetic manipulation

反转录元件是DNA片段，可以比宿主基因组更频繁地繁殖。为此，元件编码的酶逆转录酶使用反转录元件RNA作为模板来产生DNA拷贝，该拷贝通过另一种元件编码的蛋白质整合酶插入基因组中。这种逆转位的过程通常仅限于压力条件。逆转录元件可以占动植物细胞DNA含量的一半以上，但由于点突变、缺失或插入，这些元件中的大多数都不起作用。我们使用生化和遗传学的方法分析了一个具有转座能力的植物反转录转座子Tto1。我们以前的研究表明，目前(教科书)的逆转录元件倍增知识远远不足以理解Tto1的转座。除了对逆转座过程有更深刻的理解外，我们的研究还针对这一知识的应用。由于Tto1优先插入编码区，在没有自然诱导剂组织培养胁迫的情况下，受控(可诱导)转座将使Tto1成为插入突变的有力工具。这样的系统对拥有大基因组的植物特别有用，因为在这些植物中，位置克隆等技术尚未建立或过于繁琐。

Retroelements are pieces of DMA that can multiply more often than the host genome. To that end, the element-encoded enzyme reverse transcriptase uses retroelement RNA as a template to generate a DNA copy, which is inserted into the genome by another element-encoded protein, integrase. This process of retrotransposition is usually restricted to stressful conditions. Retroelements can make up more than half of the DNA content of animal and plant cells, but most of these elements are nonfunctional due to point mutations, deletions or insertions. We use biochemical and genetic methods to analyze a transpositioncompetent plant retrotransposon, Tto1. Our previous studies showed that current (textbook) knowledge of retroelement multiplication is surprisingly inadequate to understand transposition of Tto1. In addition to a more profound understanding of the retrotransposition process, our studies are directed towards application of this knowledge. Controlled (inducible) transposition in absence of the natural inducer, tissue culture stress, would turn Tto1 into a powerful tool for insertional mutagenesis, because Tto1 inserts preferentially into coding regions. Such a system would be particularly useful for plants with large genomes, where techniques such as positional cloning are not established or are too cumbersome.