Endogenous siRNAs derived from transposons and mRNAs in Drosophila somatic cells.
Small interfering RNAs (siRNAs) direct RNA interference (RNAi) in eukaryotes. In flies, somatic cells produce siRNAs from exogenous double-stranded RNA (dsRNA) as a defense against viral infection. We identified endogenous siRNAs (endo-siRNAs), 21 nucleotides in length, that correspond to transposons and heterochromatic sequences in the somatic cells of Drosophila melanogaster. We also detected endo-siRNAs complementary to messenger RNAs (mRNAs); these siRNAs disproportionately mapped to the complementary regions of overlapping mRNAs predicted to form double-stranded RNA in vivo. Normal accumulation of somatic endo-siRNAs requires the siRNA-generating ribonuclease Dicer-2 and the RNAi effector protein Argonaute2 (Ago2). We propose that endo-siRNAs generated by the fly RNAi pathway silence selfish genetic elements in the soma, much as Piwi-interacting RNAs do in the germ line.
Ghildiyal
Megha
M
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Seitz
Hervé
H
Horwich
Michael D
MD
Li
Chengjian
C
Du
Tingting
T
Lee
Soohyun
S
Xu
Jia
J
Kittler
Ellen L W
EL
Zapp
Maria L
ML
Weng
Zhiping
Z
Zamore
Phillip D
PD
D000818:Animals; D060565:Argonaute Proteins; D001483:Base Sequence; D002460:Cell Line; D004251:DNA Transposable Elements; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000235:genetics / Q000378:metabolism; D018626:Retroelements; D043244:Ribonuclease III
C433807:AGO2 protein, Drosophila; D060565:Argonaute Proteins; D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D034743:RNA-Induced Silencing Complex; D018626:Retroelements; C478069:DCR-2 protein, Drosophila; D043244:Ribonuclease III; D020365:RNA Helicases