Introduction . RNA is the essential intermediate biomolecule that transmits genetic information encoded in DNA into functional proteins. It is tightly regulated both at its birth (transcription) and death (degradation). RNA degradation is essential to maintain transcript homeostasis and clear defective RNA species. In eukaryotic cells, normal mRNA degradation is initiated by deprotection of its ends with deadenylation or decapping, followed by 5’ ?3’ degradation by XRN1 or 3’ ?5’...