Snrp

SnRNP, pronounced "snurp" is an acronym for "small nuclear ribonucleoprotein particle." This particle is involved in the process of RNA splicing, which is the separation of introns from exons in a eukaryotic pre mRNA molecule. In eukaryotes, divisions between an intron and exon sequences (as well as branch points within the intron sequences) are denoted by certain small nucleotide sequences that are the same in almost every intron. One component of a snRNP, called snRNA for "small nuclear RNA," recognizes these sequencs through complementary base pairing. To splice RNA, a group of snRNPs and helper proteins bind at the beginning of an intron sequence, as well as at the branch point of the intron sequence. With the addition of other proteins, this structure (called a spliceosome) contracts. The sequence marking the beinning of the intron is cut and covalently bonded to an adenine on the branching site, creating a lasso-shaped piece of intronic RNA. The lasso is separated from the main RNA molecule and is eventually degraded. With the help of snRNPs, the remaining RNA (the exonic regons) are combined, leaving an unbroken chain.