posttranscriptionally

Posttranscriptionally is an adverb describing processes that occur to RNA after transcription, and more broadly to RNA species produced from genes. In molecular biology, the term encompasses the maturation, modification, transport, localization, stability, and translation of RNA molecules that follow transcription from DNA. While some processing begins co-transcriptionally, many essential posttranscriptional events unfold after the RNA is synthesized.

Key posttranscriptional processes include RNA processing steps such as splicing, 5' capping, and 3' polyadenylation that shape mature RNA molecules. Alternative splicing can generate multiple transcript variants from a single gene, expanding proteomic diversity. RNA editing and chemical modification—for example A-to-I editing or methylation marks like m6A—can alter RNA function, stability, and translational efficiency by affecting how RNAs are recognized by binding proteins.

Posttranscriptionally, RNA molecules are exported from the nucleus and transported to specific cellular locales where they may be stored or locally translated. Translation and protein synthesis are regulated by interactions with RNA-binding proteins and microRNAs that influence mRNA stability and translation, often in response to developmental cues or stress.

RNA surveillance and decay pathways regulate RNA abundance. Deadenylation, decapping, and exonucleolytic decay remove RNAs that are damaged or no longer needed, while quality-control mechanisms such as nonsense-mediated decay target aberrant transcripts.

Overall, posttranscriptional regulation is a critical layer of gene expression control, interacting with transcriptional regulation to determine the cellular levels and activity of RNAs and their protein products. It is relevant to development, physiology, and disease.