The spliceosome is a protein complex made up of five small ribonucleoprotein ribonucleoprotein subunits. These snurps allow the identification of intronic regions, binding specifically to allow the excision of the non-coding region, allowing the production of mRNA from pre-mRNA, allowing translation to then happen.
U1 is the snurp, a U-rich RNA, binding to the 5’ end of the intron. U2 binds to the 3’ end of the intron. The binding of U1 and U2 first then allows U4, U5, and U6 to bind. U1 and U4 are then removed, leaving U2, U5, and U6 to pull the intron into a lariat loop which is then excised.
The role of the spliceosome is integral to pre-mRNA splicing, allowing the removal of introns. This process is essential to the function of eukaryotic cells, enabling split genes to be translated into polypeptides.