deadenylated

Deadenylated describes an RNA molecule, typically a eukaryotic mRNA, whose poly(A) tail has been shortened or removed. The poly(A) tail stabilizes transcripts and promotes translation, so deadenylation generally reduces both mRNA stability and translational efficiency, often signaling entry into decay pathways.

Deadenylation is carried out by deadenylase enzymes, with major players including the CCR4-NOT complex (containing CAF1/CCR4 subunits) and the PAN2-PAN3 complex. Other enzymes such as PARN also contribute to tail shortening in various cellular compartments. Deadenylation is commonly the first step in cytoplasmic mRNA decay: after tail shortening, transcripts may be decapped and degraded 5' to 3' by XRN1 or degraded 3' to 5' by the exosome.

Biological significance of deadenylation lies in its role as a major mode of post-transcriptional gene regulation. It modulates gene expression during development, stress responses, and cellular differentiation, and participates in processes such as circadian regulation and cell cycle control. In addition, transcripts can accumulate in repressed, deadenylated states within cytoplasmic bodies such as processing bodies, from which translation may be reinitiated if deadenylation is reversed.

Detection and measurement of poly(A) tail length and deadenylation status employ techniques such as PAT assays, TAIL-seq, and PAL-seq, which quantify tail length distributions genome-wide or for specific transcripts. Deadenylation is a dynamic and reversible aspect of post-transcriptional control, influenced by developmental cues and environmental conditions.