Chicken CR1 Elements: Prototypes of a Novel and Ancient Superfamily of Vertebrates Non-LTR Retrotransposons

Burch MCB-96-3022真核生物基因组包含来自遗传信息逆向流动的散布重复序列元件。这些反转录转座子根据它们是否含有或缺乏与逆转录病毒中发现的相似的长末端重复序列（LTR）可分为两类。鸡重复1 （CR1）元件是非ltr逆转录转座子，并编码其自身的逆转录酶。与鱼类、青蛙、爬行动物以及哺乳动物中发现的元件序列同源性表明，这些元件是存在于多个脊椎动物类别中的非ltr反转录转座子超家族的原型。CR1元件的两个不同亚家族的全长元件将被分离和表征。将确定CR1逆转录酶是否具有功能，并检测禽类和非禽类细胞培养中CR1逆转录转位事件。反转录转座子是酵母和果蝇等低等真核生物突变的主要来源，并与几种人类遗传疾病有关。它们还以其他方式导致基因组不稳定，例如，作为非互惠同源重组事件的目标。这项工作将有助于深入了解进化成功的非ltr元件CR1转位所需的机制和序列。

Burch MCB-96-3022 Eukaryotic genomes contain interspersed repetitive sequence elements that derive from the reverse flow of genetic information. These retrotransposons can be of two classes based upon whether they contain or lack long terminal repeat (LTR) sequences similar to those found in retroviruses. The chicken repeat 1 (CR1) elements are non-LTR retrotransposons and encodes its own reverse transcriptase. Sequence homology to elements found in fish, frogs, reptiles and, perhaps, mammals suggest that these elements are the prototype for a superfamily of non-LTR retrotransposons that exist in multiple vertebrate classes. Full-length elements for two distinct subfamilies of CR1 elements will be isolated and characterized. It will be determined if the CR1 reverse transcriptase is functional and avian and non-avian cell cultures will be assayed for CR1 retrotransposition events. %%% Retrotransposons are a major source of mutations in lower eukaryotes such as yeast and Drosophila and are implicated in several human genetic disorders. They also contribute to genome instability in other ways, for example, as targets for non-reciprocal homologous recombination events. This work will contribute to insight into the mechanisms and sequences required for the transposition of an evolutionary successful non-LTR element, CR1.