Initial transcript is called heterogenous nuclear RNA (hnRNA). hnRNA is then modified and becomes mRNA.

The following processes occur in the nucleus:- Capping of the 5' end (addition of the 7-methylguanosine cap)- Polyadenylation of 3' end (±200 A's)- Splicing out of introns→ Capped, tailed, and spliced transcript is called mRNA.

- mRNA is transported out of the nucleus into the cytosol, where it is translated.- mRNA quality control occurs at cytoplasmic processing bodies (P-bodies), which contain exonucleases, decapping enzymes, and microRNAs.- mRNAs may be degraded or stored in P-bodies for future translation- Poly-A polymerase does not require a template- AAUAA = polyadenylation signal