Crystal structure of a fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution. EMBO J
ABSTRACT Fibrillarin is a phylogenetically conserved protein essential for efficient processing of pre-rRNA through its association with a class of small nucleolar RNAs during ribosomal biogenesis. The protein is the antigen for the autoimmune disease scleroderma. Here we report the crystal structure of the fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution. The structure consists of two domains, with a novel fold in the N-terminal region and a methyltransferase-like domain in the C-terminal region. Mapping temperature-sensitive mutations found in yeast fibrillarin Nop1 to the Methanococcus homologue structure reveals that many of the mutations cluster in the core of the methyltransferase-like domain.
Full-textDOI: · Available from: David Boisvert, Jun 01, 2014
- "Depending on the organism, fibrillarin mass ranges between 34 and 38 KDa and was originally described in the nucleolus of Physarum polycephalum (Christensen et al., 1977). It is included in the superfamily of the Rossmann-fold S-adenosylmethionine (SAM) methyltransferases (MTases) (Wang et al., 2000). The characteristics of this superfamily include a conserved SAM-binding motif, the catalytic triad/tetrad [K-D-K-(H)] and seven-stranded β-sheet flanked by α-helices to form an α-β-α structure (Rakitina et al., 2011). "
Article: Fibrillarin from Archaea to human[Show abstract] [Hide abstract]
ABSTRACT: Fibrillarin is an essential protein that is well known as a molecular marker of transcriptionally active RNA pol I. Fibrillarin methyltransferase activity is the primary known source of methylation for more than 100 methylated sites involved in the first steps of preribosomal processing and required for structural ribosome stability. High expression levels of fibrillarin have been observed in several types of cancer cells, particularly when p53 levels are reduced, because p53 is a direct negative regulator of fibrillarin transcription. Here we show fibrillarin domain conservation, structure and interacting molecules in different cellular processes as well as with several viral proteins during virus infection. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.Biology of the Cell 03/2015; 107(6). DOI:10.1111/boc.201400077 · 3.87 Impact Factor
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- "Boxes C/D (or C9/D9), which form a specific structural motif termed kink-turn (K-turn), are required for the assembly of four core proteins, namely, 15.5K, Nop56, Nop58, and a methyltransferase, designated as Fibrillarin, to build up a functional ribonucleo-protein particle (C/D snoRNP) (Samarsky et al. 1998; Watkins et al. 2000; Klein et al. 2001; Watkins et al. 2002; Tran et al. 2004). Fibrillarin is necessary and required to localize the mature snoRNP complex to the nucleolus and also catalyzes the formation of the 29-O-Methylribose within target RNAs (Lafontaine and Tollervey 2000; Wang et al. 2000a; Verheggen et al. 2001). As shown for canonical snoRNPs, the nucleolar localization of the MBII-52 snoRNA, although lacking complementarity to rRNA or snRNA targets, has been demonstrated by FISH analysis (Vitali et al. 2005). "
ABSTRACT: Small nucleolar RNAs (snoRNAs) guide nucleotide modifications within ribosomal RNAs or spliceosomal RNAs by base-pairing to complementary regions within their RNA targets. The brain-specific snoRNA MBII-52 lacks such a complementarity to rRNAs or snRNAs, but instead has been reported to target the serotonin receptor 2C pre-mRNA, thereby regulating pre-mRNA editing and/or alternative splicing. To understand how the MBII-52 snoRNA might be involved in these regulatory processes, we isolated the MBII-52 snoRNP from total mouse brain by an antisense RNA affinity purification approach. Surprisingly, by mass spectrometry we identified 17 novel candidates for MBII-52 snoRNA binding proteins, which previously had not been reported to be associated with canonical snoRNAs. Among these, Nucleolin and ELAVL1 proteins were confirmed to independently and directly interact with the MBII-52 snoRNA by coimmunoprecipitation. Our findings suggest that the MBII-52 snoRNA assembles into novel RNA-protein complexes, distinct from canonical snoRNPs.RNA 07/2010; 16(7):1293-300. DOI:10.1261/rna.2109710 · 4.62 Impact Factor
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- "The GAR domain is methylated at arginine residues (Liu and Dreyfuss, 1995) and is responsible for interactions with various proteins including the survival motor neuron (SMN) gene product ( Jones et al., 2001) and the nuclear DEAD (Asp-Glu-Ala-Asp) box protein p68 (Nicol et al., 2000). Fibrillarin contains a centrally located RNA-binding domain which together with the C-terminal helix domain and the intervening spacer constitutes a methyltransferase-like domain that contains an S-adenosyl methionine binding motif and is responsible for fibrillarin methyltransferase activity (Wang et al., 2000a). The C-terminal helix domain appears to target fibrillarin to CBs (Snaar et al., 2000). "
ABSTRACT: The nucleolus is a dynamic subnuclear body with roles in ribosome subunit biogenesis, mediation of cell-stress responses, and regulation of cell growth. An increasing number of reports reveal that similar to the proteins of animal viruses, many plant virus proteins localize in the nucleolus to divert host nucleolar proteins from their natural functions in order to exert novel role(s) in the virus infection cycle. This chapter will highlight studies showing how plant viruses recruit nucleolar functions to facilitate virus translation and replication, virus movement and assembly of virus-specific ribonucleoprotein (RNP) particles, and to counteract plant host defense responses. Plant viruses also provide a valuable tool to gain new insights into novel nucleolar functions and processes. Investigating the interactions between plant viruses and the nucleolus will facilitate the design of novel strategies to control plant virus infections.Advances in Virus Research 01/2010; 77:119-58. DOI:10.1016/B978-0-12-385034-8.00005-3 · 3.59 Impact Factor