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5b16
From Proteopedia
X-ray structure of DROSHA in complex with the C-terminal tail of DGCR8.
Structural highlights
Function[RNC_HUMAN] Ribonuclease III double-stranded (ds) RNA-specific endoribonuclease that is involved in the initial step of microRNA (miRNA) biogenesis. Component of the microprocessor complex that is required to process primary miRNA transcripts (pri-miRNAs) to release precursor miRNA (pre-miRNA) in the nucleus. Within the microprocessor complex, DROSHA cleaves the 3' and 5' strands of a stem-loop in pri-miRNAs (processing center 11 bp from the dsRNA-ssRNA junction) to release hairpin-shaped pre-miRNAs that are subsequently cut by the cytoplasmic DICER to generate mature miRNAs. Involved also in pre-rRNA processing. Cleaves double-strand RNA and does not cleave single-strand RNA. Involved in the formation of GW bodies.[1] [2] [3] [4] [5] [6] [7] [8] [9] [DGCR8_HUMAN] Component of the microprocessor complex that acts as a RNA- and heme-binding protein that is involved in the initial step of microRNA (miRNA) biogenesis. Component of the microprocessor complex that is required to process primary miRNA transcripts (pri-miRNAs) to release precursor miRNA (pre-miRNA) in the nucleus. Within the microprocessor complex, DGCR8 function as a molecular anchor necessary for the recognition of pri-miRNA at dsRNA-ssRNA junction and directs DROSHA to cleave 11 bp away form the junction to release hairpin-shaped pre-miRNAs that are subsequently cut by the cytoplasmic DICER to generate mature miRNAs. The heme-bound DGCR8 dimer binds pri-miRNAs as a cooperative trimer (of dimers) and is active in triggering pri-miRNA cleavage, whereas the heme-free DGCR8 monomer binds pri-miRNAs as a dimer and is much less active. Both double-stranded and single-stranded regions of a pri-miRNA are required for its binding. Involved in the silencing of embryonic stem cells self-renewal.[10] [11] [12] [13] [14] [15] [16] Publication Abstract from PubMedMicroRNA maturation is initiated by RNase III DROSHA that cleaves the stem loop of primary microRNA. DROSHA functions together with its cofactor DGCR8 in a heterotrimeric complex known as Microprocessor. Here, we report the X-ray structure of DROSHA in complex with the C-terminal helix of DGCR8. We find that DROSHA contains two DGCR8-binding sites, one on each RNase III domain (RIIID), which mediate the assembly of Microprocessor. The overall structure of DROSHA is surprisingly similar to that of Dicer despite no sequence homology apart from the C-terminal part, suggesting that DROSHA may have evolved from a Dicer homolog. DROSHA exhibits unique features, including non-canonical zinc-finger motifs, a long insertion in the first RIIID, and the kinked link between Connector helix and RIIID, which explains the 11-bp-measuring "ruler" activity of DROSHA. Our study implicates the evolutionary origin of DROSHA and elucidates the molecular basis of Microprocessor assembly and primary microRNA processing. VIDEO ABSTRACT. Structure of Human DROSHA.,Kwon SC, Nguyen TA, Choi YG, Jo MH, Hohng S, Kim VN, Woo JS Cell. 2016 Jan 14;164(1-2):81-90. doi: 10.1016/j.cell.2015.12.019. Epub 2015 Dec , 31. PMID:26748718[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Large Structures | Ribonuclease III | Choi, Y G | Hohng, S | Jo, M H | Kim, V N | Kwon, S C | Nguyen, T A | Woo, J S | Endonuclease | Hydrolase | Rnase iii | Trimeric complex | Zinc finger
