Dicer-2 and R2D2 coordinately bind siRNA to promote assembly of the siRISC complexes.
In Drosophila melanogaster, the Dicer-2/R2D2 complex initiates RNA interference (RNAi) by processing long double-stranded RNA (dsRNA) into small interfering RNA (siRNA). Recent biochemical studies suggest that the Dcr-2/R2D2 complex also facilitates incorporation of siRNA into the RNA-induced silencing complex (siRISC). Here we present genetic evidence that R2D2 and Dcr-2 are both required for loading siRNA onto the siRISC complex. Consistent with this, only the Dcr-2/R2D2 complex, but neither Dcr-2 nor R2D2 alone, can efficiently interact with duplex siRNA. Furthermore, both dsRNA-binding domains of R2D2 are critical for binding to siRNA and promoting assembly of the siRISC complexes.
Liu
Xiang
X
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
Jiang
Feng
F
Kalidas
Savitha
S
Smith
Dean
D
Liu
Qinghua
Q
D000818:Animals; D029721:Drosophila Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D006720:Homozygote; D019476:Insect Proteins / Q000378:metabolism*; D016366:Open Reading Frames; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000032:analysis / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D034741:RNA, Small Interfering / Q000096:biosynthesis / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D043244:Ribonuclease III; D017384:Sequence Deletion; D013816:Thermodynamics; D019076:Transgenes
D029721:Drosophila Proteins; D019476:Insect Proteins; C478068:R2D2 protein, Drosophila; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D034743:RNA-Induced Silencing Complex; D011994:Recombinant Proteins; D006639:Histidine; C478069:DCR-2 protein, Drosophila; D043244:Ribonuclease III; D020365:RNA Helicases