TY - JOUR
T1 - Core small nuclear ribonucleoprotein particle splicing factor SmD1 modulates RNA interference in Drosophila
AU - Xiong, Xiao Peng
AU - Kurthkoti, Krishna
AU - Chang, Kung Yen
AU - Lichinchi, Gianluigi
AU - De, Nabanita
AU - Schneemann, Anette
AU - MacRae, Ian J.
AU - Rana, Tariq M.
AU - Perrimon, Norbert
AU - Zhou, Rui
PY - 2013/10/8
Y1 - 2013/10/8
N2 - RNAi is an evolutionarily conserved gene regulatory process that operates in a wide variety of organisms. During RNAi, long doublestranded RNA precursors are processed by Dicer proteins into ?21- nt siRNAs. Subsequently, siRNAs are incorporated into the RNAinduced silencing complexes (RISCs) that contain Argonaute-family proteins and guide RISC to target RNAs via complementary base pairing, leading to posttranscriptional gene silencing. Select premRNA splicing factors have been implicated in RNAi in fission yeast, worms, and flies, but the underlying molecular mechanisms are not well understood. Here, we show that SmD1, a core component of the Drosophila small nuclear ribonucleoprotein particle implicated in splicing, is required for RNAi and antiviral immunity in cultured cells and in vivo. SmD1 interacts with both Dicer-2 and dsRNA precursors and is indispensable for optimal siRNA biogenesis. Depletion of SmD1 impairs the assembly and function of the small interfering RISC without significantly affecting the expression of major canonical siRNA pathway components. Moreover, SmD1 physically and functionally associates with components of the small interfering RISC, including Argonaute 2, both in flies and in humans. Notably, RNAi defects resulting from SmD1 silencing can be uncoupled from defects in pre-mRNA splicing, and the RNAi and splicing machineries are physically and functionally distinct entities. Our results suggest that Drosophila SmD1 plays a direct role in RNAi-mediated gene silencing independently of its premRNA splicing activity and indicate that the dual roles of splicing factors in posttranscriptional gene regulation may be evolutionarily widespread.
AB - RNAi is an evolutionarily conserved gene regulatory process that operates in a wide variety of organisms. During RNAi, long doublestranded RNA precursors are processed by Dicer proteins into ?21- nt siRNAs. Subsequently, siRNAs are incorporated into the RNAinduced silencing complexes (RISCs) that contain Argonaute-family proteins and guide RISC to target RNAs via complementary base pairing, leading to posttranscriptional gene silencing. Select premRNA splicing factors have been implicated in RNAi in fission yeast, worms, and flies, but the underlying molecular mechanisms are not well understood. Here, we show that SmD1, a core component of the Drosophila small nuclear ribonucleoprotein particle implicated in splicing, is required for RNAi and antiviral immunity in cultured cells and in vivo. SmD1 interacts with both Dicer-2 and dsRNA precursors and is indispensable for optimal siRNA biogenesis. Depletion of SmD1 impairs the assembly and function of the small interfering RISC without significantly affecting the expression of major canonical siRNA pathway components. Moreover, SmD1 physically and functionally associates with components of the small interfering RISC, including Argonaute 2, both in flies and in humans. Notably, RNAi defects resulting from SmD1 silencing can be uncoupled from defects in pre-mRNA splicing, and the RNAi and splicing machineries are physically and functionally distinct entities. Our results suggest that Drosophila SmD1 plays a direct role in RNAi-mediated gene silencing independently of its premRNA splicing activity and indicate that the dual roles of splicing factors in posttranscriptional gene regulation may be evolutionarily widespread.
UR - http://www.scopus.com/inward/record.url?scp=84885365646&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84885365646&partnerID=8YFLogxK
U2 - 10.1073/pnas.1315803110
DO - 10.1073/pnas.1315803110
M3 - Article
C2 - 24067655
AN - SCOPUS:84885365646
SN - 0027-8424
VL - 110
SP - 16520
EP - 16525
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 41
ER -