A highly conserved protein complex that recognises and elicits the rapid degradation of mRNAs in which an amino-acid codon has changed to a nonsense codon; occurs when the 3' end is not protected by a 3'-poly(A) tail; degradation proceeds in the 3' to 5' direction.
Source:
GOC:lnp,
PMID:29282598,
PMID:1569946,
PMID:9032286