Dicer-dependent biogenesis of small RNAs derived from 7SL RNA.
It has been reported that decreased Dicer expression leads to Alu RNAs accumulation in human retinal pigmented epithelium cells, and Dicer may process the endogenous SINE/B1 RNAs (the rodent equivalent of the primate Alu RNAs) into small interfering RNAs (siRNAs). In this study, we aimed to address whether Dicer can process Alu RNAs and their common ancestor, 7SL RNA. Using Solexa sequencing technology, we showed that Alu-derived small RNAs accounted for 0.6% of the total cellular small RNAs in HepG2.2.15 cells, and the abundance decreased when Dicer was knocked down. However, Alu-derived small RNAs showed different characteristics from miRNAs and siRNAs, the classic Dicer-processed products. Interestingly, we found that small RNAs derived from 7SL RNA accounted for 3.1% of the total cellular small RNAs in the control cells, and the abundance dropped about 3.4 folds in Dicer knockdown cells. Dicer-dependent biogenesis of 7SL RNA-derived small RNAs was validated by northern blotting. In vitro cleavage assay using the recombinant human Dicer protein also showed that synthetic 7SL RNA was processed by Dicer into fragments of different lengths. Further functional analysis suggested that 7SL RNA-derived small RNAs do not function like miRNAs, neither do they regulate the expression of 7SL RNA. In conclusion, the current study demonstrated that Dicer can process 7SL RNA, however, the biological significance remains to be elucidated.
Institute of Genomic Medicine, Wenzhou Medical College, Wenzhou, People's Republic of China.
Yong-Feng
YF
Ren
Guiling
G
Li
Jianmin
J
Wu
Yong-Feng
YF
Xue
Yi-Jiang
YJ
Song
Lu
L
Lv
Xue-Jiao
XJ
Zhang
Kai-Fu
KF
Tang
D020087:Alu Elements / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D044127:Epigenesis, Genetic; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D020733:RNA, Small Cytoplasmic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000096:biosynthesis*; D043244:Ribonuclease III / Q000378:metabolism*; D018271:Signal Recognition Particle / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C115990:7SL RNA; D020733:RNA, Small Cytoplasmic; D034741:RNA, Small Interfering; D018271:Signal Recognition Particle; C408087:DICER1 protein, human; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases