Regulator of nonsense transcripts 1 (or Up-frameshift suppressor 1 homolog [5] ) is a protein that in humans is encoded by the UPF1 gene. [6] [7]
This gene encodes a protein that is part of a post-splicing multiprotein complex, the exon junction complex, involved in both mRNA nuclear export and mRNA surveillance. mRNA surveillance detects exported mRNAs with truncated open reading frames and initiates nonsense-mediated mRNA decay (NMD). When translation ends upstream from the last exon-exon junction, this triggers NMD to degrade mRNAs containing premature stop codons. This protein is located in both the cytoplasm and nucleus. [8] When translation ends, it interacts with the functional homolog of yeast Upf2p to trigger mRNA decapping. Use of multiple polyadenylation sites has been noted for this gene. [9]
UPF1 interacts with: