Role of the Nonsense-Mediated Decay Factor hUpf3 in the Splicing-Dependent Exon-Exon Junction Complex

@article{Kim2001RoleOT,
  title={Role of the Nonsense-Mediated Decay Factor hUpf3 in the Splicing-Dependent Exon-Exon Junction Complex},
  author={V. Narry Kim and Naoyuki Kataoka and Gideon Dreyfuss},
  journal={Science},
  year={2001},
  volume={293},
  pages={1832 - 1836}
}
Nonsense-mediated messenger RNA (mRNA) decay, or NMD, is a critical process of selective degradation of mRNAs that contain premature stop codons. NMD depends on both pre-mRNA splicing and translation, and it requires recognition of the position of stop codons relative to exon-exon junctions. A key factor in NMD is hUpf3, a mostly nuclear protein that shuttles between the nucleus and cytoplasm and interacts specifically with spliced mRNAs. We found that hUpf3 interacts with Y14, a component of… 

Complexes between the nonsense-mediated mRNA decay pathway factor human upf1 (up-frameshift protein 1) and essential nonsense-mediated mRNA decay factors in HeLa cells.

To isolate cellular complexes that are formed with Hupf1 and to explore the role of cellular proteins in NMD, a HeLa cell line is generated that stably expresses H up-frameshift protein 1 bearing a double-affinity tag and the association of poly(A)-binding protein with H upf1 is highly sensitive to treatment of the isolated complexes with RNase.

Nuclear Pnn/DRS Protein Binds to Spliced mRNPs and Participates in mRNA Processing and Export via Interaction with RNPS1

It is found that Pnn associates preferentially with mRNAs produced by splicing in vitro, and may participate, via its interaction with RNPS1, in mRNA metabolism in the nucleus, including mRNA splicing and export.

Stop codon-mediated suppression of splicing is a novel nuclear scanning mechanism not affected by elements of protein synthesis and NMD.

It is shown that SOS is a novel mechanism distinct from the known RNA surveillance mechanisms because it is not dependent on translation and is not affected by RNAi-mediated down-regulation of h upf1 and hUpf2--two key components of the NMD pathway.

Regulation of Multiple Core Spliceosomal Proteins by Alternative Splicing-Coupled Nonsense-Mediated mRNA Decay

The results show that AS-coupled NMD can have different UPF factor requirements and is likely to regulate many general components of the spliceosome, and conserved, PTC-introducing AS events are enriched in genes that encode core spliceOSomal proteins.

The Interaction between Cap-binding Complex and RNA Export Factor Is Required for Intronless mRNA Export*

Analysis of the RNA-binding protein complexes revealed that REF associates with β-globin mRNA at the region other than the EJC deposition site, and co-injection of CBP20 and REF may play a stimulatory role to export the capped intronless mRNAs.

Binding of a novel SMG-1-Upf1-eRF1-eRF3 complex (SURF) to the exon junction complex triggers Upf1 phosphorylation and nonsense-mediated mRNA decay.

The SMG-1-mediated phosphorylation of Upf1 occurs on the association of SURF with EJC, which provides the link between the EJC and recognition of PTCs and triggers NMD.

5' exon interactions within the human spliceosome establish a framework for exon junction complex structure and assembly.

A general consequence of pre-mRNA splicing is the stable deposition of several proteins 20-24 nucleotides (nt) upstream of exon-exon junctions on spliced mRNAs. This exon junction complex (EJC)
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