Xrn1-sensitive Unstable Transcripts (XUTs) are 3′-extended isoforms of stable lncRNAs
Nonsense-Mediated Decay preferentially targets long XUTs with single-stranded 3′ end
Antisense XUTs form double-stranded RNA in vivo
Formation of double-stranded RNA protects XUTs from Nonsense-Mediated Decay