A spliceosome's a complex of specialized RNA and protein subunits that removes introns from a transcribed pre-mRNA (hnRNA) segment. This process's generally referred to as splicing. Composition Each spliceosome's composed of five small nuclear RNA proteins, called snRNPs, (pronounced "snurps") and a range of non-snRNP associated protein factors. The snRNPs that make up the nuclear spliceosome are named U1, U2, U4, U5, and U6, and participate in several RNA-RNA and RNA-protein interactions. The… (More on Spliceosome)