A Two-Layered Targeting Mechanism Underlies Nuclear RNA Sorting by the Human Exosome (Cell Reports)

Wu et al. demonstrate that the nuclear exosome adaptor NEXT targets poly(A)- RNAs with poorly defined 3´ ends, whereas the PAXT connection targets poly(A)+ RNAs derived from canonical poly(A) sites. NEXT substrates become polyadenylated in the absence of NEXT, causing fail-safe RNA decay via PAXT.