Introns – self-splicing gene segments – are another avenue for altering the expression of genetic codes.
Proteins are a cell’s workforce. Genes are merely templates for producing proteins and other bioproducts that work in concert with proteins. Any mechanism that alters protein operation has the potential to alter the genome via feedback.
Inteins are self-splicing protein segments which can excise themselves from larger protein molecules and rejoin a polypeptide chain (extein) via a peptide bond. In prokaryotes, inteins are known to function as genome maintenance proteins.
Inteins have been called protein introns. Both introns and inteins are agents in gene expression and regulation.