Functional anatomy of the Drosophila microRNA-generating enzyme.
In Drosophila melanogaster, the multidomain RNase III Dicer-1 (Dcr-1) functions in tandem with the double-stranded (ds)RNA-binding protein Loquacious (Loqs) to catalyze the maturation of microRNAs (miRNAs) from precursor (pre)-miRNAs. Here we dissect the molecular mechanism of pre-miRNA processing by the Dcr-1-Loqs complex. The tandem RNase III (RIII) domains of Dcr-1 form an intramolecular dimer such that one RIII domain cleaves the 3' strand, whereas the other cuts the 5' strand of pre-miRNA. We show that the functional core of Dcr-1 consists of a DUF283 domain, a PAZ domain, and two RIII domains. Dcr-1 preferentially associates with the Loqs-PB splice isoform. Loqs-PB uses the second dsRNA-binding domain to bind pre-miRNA and the third dsRNA-binding domain to interact with Dcr-1. Both domains of Loqs-PB are required for efficient miRNA production by enhancing the affinity of Dcr-1 for pre-miRNA. Thus, our results provide further insights into the functional anatomy of the Drosophila miRNA-generating enzyme.
Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038.
Xuecheng
X
Ye
Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038.
Zain
Z
Paroo
Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038. Electronic address: Qinghua.Liu@UTsouthwestern.edu.
Qinghua
Q
Liu
D000818:Animals; D019281:Dimerization; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D035683:MicroRNAs / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; C503213:Loqs protein, Drosophila; D035683:MicroRNAs; D046912:Multiprotein Complexes; D020033:Protein Isoforms; D012322:RNA Precursors; D016601:RNA-Binding Proteins; C515033:Dcr-1 protein, Drosophila; D043244:Ribonuclease III; D020365:RNA Helicases