| 2018 |
The intron-hosted box C/D snoRNA snoRD86 acts in cis as a sensor controlling NOP56 levels: excess snoRNP core proteins cause snoRD86 to adopt alternative RNP conformations that dictate usage of nearby alternative splice donors in the NOP56 pre-mRNA, triggering generation of a cytoplasmic snoRD86-containing NOP56-derived lncRNA via the nonsense-mediated decay pathway — a feedback mechanism that couples snoRNP core protein availability to NOP56 production. |
Alternative splicing analysis, NMD reporter assays, RNA structure probing, overexpression/depletion of snoRNP core proteins with functional readouts in human cells |
Molecular Cell |
High |
30220559
|
| 2009 |
Fibrillarin and NOP56 directly interact in vivo prior to assembly into box C/D snoRNPs; this interaction requires the alpha-helix domain of fibrillarin (not the GAR or RNA-binding domain) and does not require RNA. Disrupting either protein's localization impairs their association with box C/D snoRNPs. |
Relocalization/affinity-tag delocalization of core box C/D proteins followed by co-immunoprecipitation and localization analysis in mammalian cells |
Experimental Cell Research |
Medium |
19331828
|
| 2021 |
High-resolution crystal structure of eukaryotic Nop1 (fibrillarin) from S. cerevisiae bound to the amino-terminal domain of Nop56 was solved; the interaction interface differs substantially from the archaeal orthologs, demonstrating that eukaryotic Nop56 recruits the methyltransferase to the box C/D RNP through a protein-protein interface distinct from that in archaea. |
X-ray crystallography with functional comparison to archaeal structures |
RNA |
High |
33483369
|
| 2007 |
Crystal structure of archaeal Nop56/58-fibrillarin complex from Pyrococcus furiosus (at 2.7 Å) bound to S-adenosyl-L-methionine confirmed the generality of the bipartite/symmetric dimer arrangement; the distinct conformation of Nop56/58 compared to the Archaeoglobus fulgidus structure revealed flexibility via hinge motion, repositioning fibrillarin catalytic sites, suggesting simultaneous positioning of two catalytic sites at two target sites of a bipartite guide RNA. |
X-ray crystallography and computational normal mode analysis |
Journal of Molecular Biology |
High |
17617422
|
| 2006 |
In archaeal box C/D sRNPs, the coiled-coil domain of Nop56/58 is dispensable for core protein binding and sRNP assembly but is required for sRNP-guided nucleotide 2'-O-methylation; Nop56/58 self-dimerization and Nop56/58-fibrillarin dimerization are mutually exclusive interactions; deletion of the coiled-coil domain disrupts RNP structure essential for methylation without preventing assembly. |
Site-directed mutagenesis, protein pull-down assays, in vitro methylation assays, nuclease probing of sRNP structure |
RNA |
High |
16601205
|
| 2012 |
The N-terminal domain (NTD) of archaeal Nop56/58 mediates an exceptionally stable interaction with fibrillarin; mutations that did not affect fibrillarin binding or sRNP assembly still disrupted sRNP-guided nucleotide modification, revealing a direct role for Nop56/58 in methyltransferase activity beyond scaffolding. Cross-linking confirmed Nop56/58 contacts the target RNA substrate. The NTD crystal structure (1.7 Å) showed conservation despite low sequence identity among archaeal homologs. |
Site-directed mutagenesis, in vitro methylation assay, chemical and thermal denaturation, RNA cross-linking, X-ray crystallography |
Journal of Biological Chemistry |
High |
22496443
|
| 2002 |
Xenopus laevis NOP56 (XNop56p) was identified as a common component of X. laevis box C/D snoRNPs; it is not essential for snoRNA stability; its transcript initiates with a pyrimidine tract and contains an intronic snoRNA, but it is not translationally regulated in a growth-dependent manner (i.e., it is not a TOP gene). |
cDNA cloning, co-immunoprecipitation with box C/D snoRNPs, 5' end mapping, polysome analysis |
Biochimica et Biophysica Acta |
Medium |
12020815
|
| 2013 |
NOP56 (Nol5a) was identified as a gene hyperactivated by Burkitt's lymphoma-associated Myc mutants and was shown to be necessary for Myc-induced cell transformation; Nol5a/NOP56 enhances wild-type Myc-induced cell transformation and increases the size of Myc-induced tumors, placing NOP56 downstream of Myc as a rate-limiting effector for transformation. |
Gene expression profiling, RNAi knockdown/overexpression with transformation assays and in vivo tumor growth assays |
Oncogene |
Medium |
24013231
|
| 2022 |
NOP56 depletion in KRAS-mutant lung cancer cells increases ROS levels and creates synthetic lethality with mTOR inhibition; mechanistically, cells with reduced NOP56 rely on mTOR signaling to balance oxidative stress, and IRE1α-mediated unfolded protein response activates mTOR through p38 MAPK in this context. Co-targeting NOP56 and mTOR profoundly enhances tumor cell death in vitro and in vivo. |
RNAi/shRNA knockdown, CRISPR/Cas9 knockout, flow cytometry for ROS, Western blot, chemical inhibitor screen, xenograft models |
Journal of Experimental & Clinical Cancer Research |
Medium |
35039048
|
| 2022 |
Loss-of-function of nop56 in zebrafish causes severe neurodegeneration characterized by absence of cerebellum, reduced spinal cord neurons, high CNS apoptosis, and impaired movement, with disrupted expression of genes related to the C/D box complex, balance, and CNS development, establishing NOP56 as essential for vertebrate CNS development and function. |
Zebrafish loss-of-function mutant, fluorescence microscopy, apoptosis assays, gene expression analysis |
Biomedicines |
Medium |
36009362
|
| 2011 |
Expansion of an intronic GGCCTG hexanucleotide repeat in NOP56 causes SCA36; RNA foci form in lymphoblastoid cells from affected subjects, and the expanded (GGCCUG)n RNA binds the RNA-binding protein SRSF2 (but not CUG6), as shown by gel-shift assay, indicating RNA gain-of-function toxicity. |
Genetic linkage analysis, FISH for RNA foci, gel-shift assay, segregation analysis |
American Journal of Human Genetics |
Medium |
21683323
|
| 2020 |
The intronic GGCCTG repeat expansion in NOP56 undergoes repeat-associated non-AUG (RAN) translation to produce dipeptide repeat proteins (DPRs) including poly(GP) and poly(PR); poly(GP) in SCA36 is produced via canonical AUG-mediated translation from intron-retained repeat RNAs and exists as a soluble species without TDP-43 pathology, in contrast to c9ALS/FTD where chimeric DPR species cause aggregation. |
RAN translation detection in patient tissue, immunoassays for DPR proteins, comparison of solubility profiles |
Neuron |
Medium |
32375063
|
| 2025 |
NOP56 intron 1 GGCCTG repeat RAN translation occurs in all reading frames of the sense strand; translation initiates in a 5'-cap-dependent manner from near-cognate start codons upstream of the repeat in each frame; longer GGCCTG repeats enhance RAN translation; and a frameshift occurs within the GGCCUG repeat during translation. |
Cell-free translation systems with reporter constructs and mutagenesis |
Journal of Biological Chemistry |
Medium |
40015643
|
| 2013 |
NOP56 protein levels progressively decrease selectively in large motor neurons of lumbar and cervical spinal cord in SOD1-G93A ALS model mice from the early symptomatic stage, preceding reductions in TDP-43 and FUS, implicating early NOP56 loss in motor neuron degeneration. |
Immunohistochemistry and protein expression analysis across disease stages in transgenic ALS mice |
Neurological Research |
Low |
23582672
|
| 2026 |
NOP56 interacts with fibrillarin (FBL) and activates the PI3K/AKT/CREB signaling pathway in hepatocellular carcinoma; NOP56 knockdown lowers FBL levels and suppresses PI3K/AKT/CREB activity, while FBL overexpression partially rescues apoptotic effects of NOP56 silencing. |
Co-immunoprecipitation, Western blot, RNAi knockdown, overexpression rescue, xenograft models |
Frontiers in Oncology |
Low |
41568368
|
| 2026 |
NOP56 promotes p53 degradation in colorectal cancer through suppression of SIRT1 and activation of p300; NOP56 depletion increases p53 stability and acetylation via the SIRT1/p300 axis, as supported by evidence of direct interaction and colocalization of NOP56 with SIRT1 and p300. |
RNAi knockdown, co-immunoprecipitation, colocalization, Western blot, xenograft models |
International Journal of Biological Sciences |
Low |
42157947
|
| 2026 |
NOP56 activates MYC signaling by regulating IRES-dependent translation, and MYC in turn transcriptionally upregulates NOP56 expression, creating a positive feedback loop that enhances ribosome biogenesis and drives NSCLC progression; promoter hypomethylation also contributes to NOP56 upregulation. |
Luciferase reporter assay for IRES translation, chromatin immunoprecipitation, bisulfite DNA sequencing, RNA sequencing, functional overexpression/knockdown assays |
Cancers |
Low |
41827688
|
| 2021 |
In miiuy croaker, NOP56 negatively regulates MyD88-mediated NF-κB signaling; the NOSIC domain of NOP56 is responsible for suppressing MyD88 protein expression; NOP56 overexpression inhibits MyD88 protein levels while NOP56 siRNA knockdown increases them. |
Overexpression, siRNA knockdown, Western blot, domain deletion analysis in fish cells |
Fish & Shellfish Immunology |
Low |
34774735
|
| 2025 |
In a preprint, NOP56 expression was downregulated by unfolded protein response (UPR) alongside FBL and NHP2L1; reduced C/D box snoRNP function during UPR alters rRNA 2'-O-methylation and translational fidelity including effects on nonsense suppression, frameshifts, ribosome pausing, and IRES-dependent translation initiation. |
qRT-PCR for expression, FBL knockdown with rRNA methylation assay and translational fidelity reporter assays |
bioRxivpreprint |
Low |
|