High Quality Content by WIKIPEDIA articles! The U7 small nuclear RNA (U7 snRNP) is an RNA molecule involved in the splicing of metazoan histone pre-mRNAs, which are spliced by a different mechanism than nuclear pre-mRNAs and self-splicing introns. The 5` end of U7 RNA is thought to base-pair to a conserved spacer element downstream of the cleavage site in histone pre-mRNA.