Figure 3.

The ‘yet to be discovered’ roles of IR and possible implications for cancer. (A) Acting as competing endogenous RNA or miRNA sponges, retained introns harbouring MREs might divert miRNAs away from their canonical target. MRE, miRNA response element; UTR, untranslated region. (B) Compensatory feedback after degradation of PTC-containing IR transcript via NMD. NMD – nonsense mediated decay; COMPASS – Complex Proteins Associated with Set1; Upf3 – nonsense-mediated mRNA decay protein 3. (C) Acting as an alternative source of polyadenylation sites to generate truncated protein isoforms. pA – polyadenylation site. (D) Source of stable introns interacting with the spliceosome wherein cancer cells survive under starvation conditions.