Hipp, C. ; Mussgnug, S.* ; Choudhary, P.* ; Kang, H.-S. ; Asami, S. ; Sastre, J.* ; Donau, C.* ; Böttcher, R.* ; Gemmecker, G. ; Boekhoven, J.* ; Förstemann, K.* ; Sattler, M.
     
 
    
        
Molecular mechanisms of biomolecular condensate formation in Drosophila melanogaster siRNA biogenesis.
    
    
        
    
    
        
        Nucleic Acids Res. 53:gkaf664 (2025)
    
    
    
		
		
			
				Biogenesis of small interfering RNAs (siRNA) in Drosophila melanogaster involves the processing of double-stranded RNA (dsRNA) by Dcr-2 with Loqs-PD/R2D2 and Ago2. Here, we show that Loqs-PD and Ago2 are found in biomolecular condensates in vivo and display liquid-liquid phase separation in vitro. The phase separation of Loqs-PD depends on the RNA-binding capability of its double-stranded RNA-binding domains and is further modulated by the preceding N-terminal region. An intrinsically disordered region in Ago2 (Ago2IDR) forms condensates in the presence of RNA in vitro. Combining NMR spectroscopy and mutational analysis, we show that Ago2IDR/RNA condensates are fluid, with significant polypeptide backbone flexibility, and are stabilized by a dense network of interactions involving arginine and aromatic side chains. Co-partitioning of Loqs-PD into Ago2IDR/dsRNA condensates depends on its ability to bind RNA. An RNase III enzyme can act on Ago2IDR/dsRNA condensates and reduce phase separation. Our results indicate that the unique features of the Ago2 IDR, which are broadly conserved in arthropods, drive biomolecular condensate formation, suggesting that phase separation plays a role in siRNA processing in Drosophila, potentially tuning the efficiency of dsRNA-mediated antiviral defense.
			
			
				
			
		 
		
			
				
					
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        Publikationstyp
        Artikel: Journalartikel
    
 
    
        Dokumenttyp
        Wissenschaftlicher Artikel
    
 
    
        Typ der Hochschulschrift
        
    
 
    
        Herausgeber
        
    
    
        Schlagwörter
        Risc Loading Complex; Phase-separation; Rna; Protein; R2d2; Diffusion; Dynamics; Domain; Gradient; Residues
    
 
    
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        Sprache
        englisch
    
 
    
        Veröffentlichungsjahr
        2025
    
 
    
        Prepublished im Jahr 
        0
    
 
    
        HGF-Berichtsjahr
        2025
    
 
    
    
        ISSN (print) / ISBN
        0305-1048
    
 
    
        e-ISSN
        1362-4962
    
 
    
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	    Band: 53,  
	    Heft: 14,  
	    Seiten: ,  
	    Artikelnummer: gkaf664 
	    Supplement: ,  
	
    
 
  
        
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            Verlag
            Oxford University Press
        
 
        
            Verlagsort
            Great Clarendon St, Oxford Ox2 6dp, England
        
 
	
        
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        Begutachtungsstatus
        Peer reviewed
    
 
     
    
        POF Topic(s)
        30203 - Molecular Targets and Therapies
    
 
    
        Forschungsfeld(er)
        Enabling and Novel Technologies
    
 
    
        PSP-Element(e)
        G-503000-001
    
 
    
        Förderungen
        Fonds der Chemischen Industrie
    
 
    
        Copyright
        
    
 	
    
    
    
    
    
        Erfassungsdatum
        2025-07-22