Assembly and Maturation of the U3 snoRNP in the Nucleoplasm in a Large Dynamic Multiprotein Complex (2004)

Author(s): Watkins NJ, Lemm I, Ingelfinger D, Schneider C, Hoßbach M, Urlaub H, Lührmann R

    Abstract: The assembly and maturation of box C/D snoRNPs, factors essential for ribosome biogenesis, occur in the nucleoplasm. To investigate this process we have analysed non-snoRNP factors associated with the nucleoplasmic human U3 snoRNA. We show that both the precursor and mature length nucleoplasmic U3 snoRNAs are present in larger multi-protein complexes that contain the core box C/D proteins as well as many non-snoRNP factors linked to snoRNP assembly (TIP48, TIP49, Nopp140), RNA processing (TGS1, La, LSm 4, hRrp46), and subcellular localisation (CRM1, PHAX). Using RNAi we show that most of these factors are essential for box C/D snoRNA accumulation. Furthermore, we demonstrate that the core proteins undergo a restructuring event that stabilises their binding to the snoRNA. Importantly restructuring, which may be mediated by the putative remodelling factor TIP49, appears to be linked to nucleolar localisation. We believe that the assembly complex co-ordinates snoRNA processing, snoRNP assembly, restructuring and localisation.

      • Date: 2004-12-02
      • Journal: Molecular Cell
      • Volume: 16
      • Issue: 5
      • Pages: 789-798
      • Publisher: Cell Press
      • Publication type: Article
      • Bibliographic status: Published

      Dr Nick Watkins
      Senior Lecturer