snRNPs (pronounced "snurps"), or
small nuclear ribonucleo proteins, are
RNA-protein complexes that combine with unmodified
pre-mRNA and various other proteins to form a
spliceosome, a large RNA-protein molecular complex upon which
splicing of
pre-mRNA occurs. The action of snRNPs is essential to the removal of
introns from
pre-mRNA, a critical aspect of
post-transcriptional modification of RNA, occurring only in the
nucleus of
eukaryotic cells. Additionally,
U7 snRNP is not involved in splicing at all, as U7 snRNP is responsible for processing the 3' stem-loop of histone pre-mRNA.
