Specialized piRNA pathways act in germline and somatic tissues of the Drosophila ovary.
In Drosophila gonads, Piwi proteins and associated piRNAs collaborate with additional factors to form a small RNA-based immune system that silences mobile elements. Here, we analyzed nine Drosophila piRNA pathway mutants for their impacts on both small RNA populations and the subcellular localization patterns of Piwi proteins. We find that distinct piRNA pathways with differing components function in ovarian germ and somatic cells. In the soma, Piwi acts singularly with the conserved flamenco piRNA cluster to enforce silencing of retroviral elements that may propagate by infecting neighboring germ cells. In the germline, silencing programs encoded within piRNA clusters are optimized via a slicer-dependent amplification loop to suppress a broad spectrum of elements. The classes of transposons targeted by germline and somatic piRNA clusters, though not the precise elements, are conserved among Drosophilids, demonstrating that the architecture of piRNA clusters has coevolved with the transposons that they are tasked to control.
Malone
Colin D
CD
Watson School of Biological Sciences, Cold Spring Harbor, NY 11724, USA.
Brennecke
Julius
J
Dus
Monica
M
Stark
Alexander
A
McCombie
W Richard
WR
Sachidanandam
Ravi
R
Hannon
Gregory J
GJ
D000818:Animals; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D020868:Gene Silencing; D009154:Mutation; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism*; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D018626:Retroelements
D034741:RNA, Small Interfering; D022661:RNA, Untranslated; D018626:Retroelements