Intein is an intervening polypeptide which can catalytic self-cleavage from a pre-protein accompanied by the concomitant joining of the two flanking polypeptides (the extein) through a peptide bond.
Now, along with insulin, beta cells also secrete islet amyloid polypeptide, or amylin, so while beta cells are cranking out insulin they also secrete an increased amount of amylin.
This means that their RNA is actually mRNA, and the host cell ribosomes use this mRNA to make a long polyprotein chain, which is then broken into smaller pieces by viral proteases.
Among these are SNRPN which stands for Small Nuclear Ribonucleoprotein Polypeptide N and a cluster of snoRNAs, which stands for small nucleolar RNAs; these genes all have protein products that modify other RNAs.