What post-transcriptional modifications occur to eukaryotic mRNA?

Eukaryotic pre-mRNA undergoes three major modifications: 5' capping (addition of 7-methylguanosine cap that protects from degradation and aids ribosome binding), 3' polyadenylation (addition of poly-A tail of 100-250 adenines for stability and export), and splicing (removal of introns and joining of exons by the spliceosome). These modifications occur in the nucleus before export to the cytoplasm and are essential for mRNA stability, nuclear export, and efficient translation.