Post-transcriptional

• Editing of primary mRNA and removal of introns to produce mature mRNA; Intron: Gene section that doesn’t code for amino acid, Exon: Does code for amino acids
• Before leaving nucleus, mRNA is modified by addition of guanine to 5’ chan end (cap); promotes translation once mRNA reaches ribosomes
• 3’ chain end, about 100 adenines are added to give poly-A tail; believed to act as signal for mRNA export from nucleus and protection from enzyme action in cytoplasm
• Splicing: Spliceosome cases intron to form a loop shape, and is excised, then exons are spliced together; Alternative Splicing: Can remove exons, mRNA can now leave nucleus