snRNP

Small nuclear RNA (snRNP, or 'snurps'), joins with proteins to form spliceosomes. The spliceosomes govern alternative splicing.

The background to this is that, in eukaryotes, most genes code for a protein in separated strings of DNA. This is because, of a total gene, coding bits (exons) are separated by non-coding bits (introns). The process called alternative splicing can produce many possible proteins from the gene parts because the proteins are put together in different ways. Alternative splicing produces alternative messenger RNAs, and these produce different proteins. Spliceosomes control the details of the splicing.

The two essential components of snRNPs are protein molecules and RNA. The RNA found within each snRNP particle is known as small nuclear RNA, or snRNA, and is usually about 150 nucleotides in length. The snRNA component of the snurp is specific to individual introns because it 'recognises' the sequences of critical signals at the ends and branch sites of introns. The snRNA in snurps is similar to ribosomal RNA: it acts both as an enzyme (catalyst) and builds structure.

SnRNPs were discovered by Michael Lerner and Joan Steitz. Thomas Cech and Sidney Altman also played a role in the discovery, winning the Nobel Prize for Chemistry in 1989 for their independent discoveries that RNA can act as a catalyst in cell development.