Observing and quantifying transposable element activity inside living cells

evolution, transposable elements

Lee, Jia Gloria

关键词: evolution, transposable elements;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/105648/LEE-DISSERTATION-2019.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Evolution is driven by the activity of transposable elements, ‘jumping genes’ that are ubiquitous to all life forms. To study their dynamics in higher resolution, transposable elements were genetically engineered for tunable expression inside living cells, then tracked in real time using fluorescence microscopy. We show that even simple transposable element systems, such as the bacterial transposon IS608, exhibit spatial and temporal variation across a population. By quantifying these variations in transposition dynamics, we generated a model of how transposition activity levels may be a hereditary trait. We also find that the activity of the human retrotransposon LINE-1 is lethal to bacterial cell growth, and propose that transposable element activity may have played a role in the early evolution of eukaryotes. Again, by quantifying how LINE-1 expression decreases bacterial growth rate, we generated a model of retrotransposon proliferation in the genome of simple cells. To further test our hypothesis, we transferred this tunable LINE-1 system into yeast cells, and began replicating experiments in a simple single-celled eukaryote. These studies highlight the importance of quantifying variations in transposable element activity across a population, and investigate the role of transposable element activity in the emergence of complex life.