title: Reexamining the P-Element Invasion of Drosophila melanogaster Through the Lens of piRNA Silencing.
abstract: Transposable elements (TEs) are both important drivers of genome evolution and genetic parasites with potentially dramatic consequences for host fitness. The recent explosion of research on regulatory RNAs reveals that small RNA-mediated silencing is a conserved genetic mechanism through which hosts repress TE activity. The invasion of the Drosophila melanogaster genome by P elements, which happened on a historical timescale, represents an incomparable opportunity to understand how small RNA-mediated silencing of TEs evolves. Repression of P-element transposition emerged almost concurrently with its invasion. Recent studies suggest that this repression is implemented in part, and perhaps predominantly, by the Piwi-interacting RNA (piRNA) pathway, a small RNA-mediated silencing pathway that regulates TE activity in many metazoan germlines. In this review, I consider the P-element invasion from both a molecular and evolutionary genetic perspective, reconciling classic studies of P-element regulation with the new mechanistic framework provided by the piRNA pathway. I further explore the utility of the P-element invasion as an exemplar of the evolution of piRNA-mediated silencing. In light of the highly-conserved role for piRNAs in regulating TEs, discoveries from this system have taxonomically broad implications for the evolution of repression.
authors: Department of Biology and Biochemistry, University of Houston, Texas 77004 eskelleher@uh.edu.
authors: Erin S
authors: 0000-0002-1827-067X
authors: ES
authors: Kelleher
mesh_terms: D000818:Animals; D004251:DNA Transposable Elements / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D019143:Evolution, Molecular; D020868:Gene Silencing; D049750:Genome, Insect; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic
chemical_list: D004251:DNA Transposable Elements; D034741:RNA, Small Interfering
keywords: P element; hybrid dysgenesis; piRNA; transposable element