Post-transcriptional regulation comprises the eukaryote-specific processing steps that convert a primary RNA transcript into mature messenger RNA, controlling both its coding content and its stability before translation. The primary transcript is copied base-for-base from DNA and then edited by the spliceosome, which excises non-coding introns and ligates the protein-coding exons together; the transcript additionally acquires a 5' cap and a 3' poly-A tail, modifications that shield the ends from exonucleolytic degradation, promote ribosomal binding, and regulate nuclear export. A further, rarer mechanism — RNA editing — alters the nucleotide sequence of the RNA itself through enzyme-catalyzed insertion, deletion, or base substitution, so that the mature transcript need not correspond exactly to the gene. The topic belongs to molecular biology as the regulatory layer of gene expression situated between transcription and translation.
Post-transcriptional regulation comprises the eukaryote-specific processing steps that convert a primary RNA transcript into mature messenger RNA, controlling both its coding content and its stabilit…