RdRP-synthesized antisense ribosomal siRNAs silence pre-rRNA via the nuclear RNAi pathway.
Expression of rRNA affects cell growth and proliferation, but mechanisms that modulate rRNA levels are poorly understood. We conducted a genetic screen for factors that negatively regulate generation of endogenous short interfering RNA (endo-siRNA) in Caenorhabditis elegans and identified a suppressor of siRNA (susi-1) and antisense ribosomal siRNAs (risiRNAs). risiRNAs show sequence complementary to 18S and 26S rRNAs and require RNA-dependent RNA polymerases (RdRPs) for their production. They act through the nuclear RNA interference (RNAi) pathway to downregulate pre-rRNA. Stress stimuli, including low temperature and UV irradiation, induced the accumulation of risiRNAs. SUSI-1 is a homolog of the human DIS3L2 exonuclease involved in 3'-5' degradation of oligouridylated RNAs. In susi-1 mutant and in low temperature-treated animals, 3'-tail oligouridylated 26S rRNA accumulated. The injection of oligouridylated rRNA elicited nuclear accumulation of NRDE-3. Our findings identify a new subset of 22G-RNAs that regulate pre-rRNA expression and a mechanism to maintain rRNA homeostasis.
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Xufei
0000-0001-7119-8390
X
Zhou
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Xuezhu
X
Feng
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Hui
H
Mao
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Mu
M
Li
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Fei
F
Xu
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Kai
K
Hu
School of Life Sciences, CAS Center for Excellence in Molecular Cell Science, University of Science and Technology of China, Hefei, China.
Shouhong
0000-0001-7700-9634
S
Guang
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism / Q000528:radiation effects; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism* / Q000528:radiation effects; D015536:Down-Regulation / Q000235:genetics / Q000528:radiation effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D059014:High-Throughput Nucleotide Sequencing; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D034622:RNA Interference; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability / Q000528:radiation effects; D016372:RNA, Antisense / Q000235:genetics* / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism / Q000528:radiation effects; D013696:Temperature; D014466:Ultraviolet Rays; D014529:Uridine / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D012322:RNA Precursors; D016372:RNA, Antisense; D012335:RNA, Ribosomal; D034741:RNA, Small Interfering; C065096:RNA, ribosomal, 26S; D049452:Green Fluorescent Proteins; D012324:RNA-Dependent RNA Polymerase; D014529:Uridine