Souames Sémi, Bazin Claude, Bonnivard Eric, Higuet Dominique
Institut Jacques Monod, Universités Paris 6 et 7, CNRS, Laboratoire Dynamique du Génome et Evolution, Paris, France.
Mol Biol Evol. 2003 Dec;20(12):2055-66. doi: 10.1093/molbev/msg221. Epub 2003 Aug 29.
The hobo transposable element of Drosophila melanogaster is known to induce a hybrid dysgenesis syndrome. Moreover it displays a polymorphism of a microsatellite in its coding region: TPE repeats. In European populations, surveys of the distribution of hobo elements with regard to TPE repeats revealed that the 5TPE element is distributed along a frequency gradient, and it is even more frequent than the 3TPE element in Western populations. This suggests that the invasive ability of the hobo elements could be related to the number of TPE repeats they contain. To test this hypothesis we monitored the evolution of 16 lines derived from five initial independent transgenic lines bearing the 3TPE element and/or the 5TPE element. Four lines bearing 5TPE elements and four bearing 3TPE elements were used as a noncompetitive genetic background to compare the evolution of the 5TPE element to that of the 3TPE element. Eight lines bearing both elements provided a competitive genetic context to study potential interactions between these two elements. We studied genetic and molecular aspects of the first 20 generations. At the molecular level, we showed that the 5TPE element is able to spread within the genome at least as efficiently as the 3TPE element. Surprisingly, at the genetic level we found that the 5TPE element is less active than the 3TPE element, and moreover may be able to regulate the activity of the 3TPE element. Our findings suggest that the invasive potential of the 5TPE element could be due not only to its intrinsic transposition capacity but also to a regulatory potential.
已知果蝇的流浪汉转座元件会诱发杂种不育综合征。此外，它在编码区显示出微卫星多态性：TPE重复序列。在欧洲种群中，关于TPE重复序列对流浪汉元件分布的调查显示，5TPE元件沿频率梯度分布，并且在西方种群中它比3TPE元件更常见。这表明流浪汉元件的入侵能力可能与其所含TPE重复序列的数量有关。为了验证这一假设，我们监测了来自五个初始独立转基因品系（携带3TPE元件和/或5TPE元件）的16个品系的进化情况。四个携带5TPE元件的品系和四个携带3TPE元件的品系被用作非竞争性遗传背景，以比较5TPE元件和3TPE元件的进化情况。八个同时携带这两种元件的品系提供了竞争性遗传背景，以研究这两种元件之间的潜在相互作用。我们研究了前20代的遗传和分子方面。在分子水平上，我们表明5TPE元件在基因组内扩散的效率至少与3TPE元件相同。令人惊讶的是，在遗传水平上我们发现5TPE元件比3TPE元件活性更低，而且它可能能够调节3TPE元件的活性。我们的研究结果表明，5TPE元件的入侵潜力不仅可能归因于其内在的转座能力，还可能归因于其调节潜力。
