snrn

Small nuclear ribonucleoproteins, commonly abbreviated as snRNPs or pronounced "snurps," are essential complexes found within the nucleus of eukaryotic cells. They are fundamental components of the spliceosome, a large molecular machine responsible for pre-messenger RNA splicing.

Each snRNP particle consists of two main parts: one or more small nuclear RNA molecules and a set of associated proteins. The RNA components, such as U1, U2, U4, U5, and U6 snRNA, are rich in uridine, which is reflected in their naming convention. These RNA sequences are highly conserved across species, underscoring their critical functional role. The proteins bound to the snRNA provide structural stability and facilitate the catalytic activities of the spliceosome.

The primary function of snRNPs is to recognize specific sequences at the boundaries of introns, the non-coding regions within a gene. They assemble in a precise order onto the pre-mRNA strand, forming the active spliceosome. This complex then catalyzes the excision of introns and the joining of exons, the coding sequences, to produce a mature mRNA transcript. This process is vital for generating a diverse repertoire of proteins from a limited set of genes.

Defects in the assembly or function of snRNPs can lead to errors in RNA splicing, which are implicated in various human diseases, including spinal muscular atrophy and certain forms of cancer. Due to their central role in gene expression, snRNPs remain a major focus of molecular biology research.