spliceosomiin

The spliceosome is a large and dynamic molecular machine found within the nucleus of eukaryotic cells. It is primarily responsible for the process of RNA splicing, a critical step in gene expression. During transcription, genes are initially transcribed into pre-messenger RNA (pre-mRNA). This pre-mRNA contains both coding regions, called exons, and non-coding regions, called introns. The spliceosome's main function is to remove these introns and join the exons together to form mature messenger RNA (mRNA), which can then be translated into protein.

This complex assembly is composed of small nuclear ribonucleoproteins (snRNPs), often referred to as "snips," and a variety of associated proteins. The snRNPs are themselves made up of small nuclear RNAs (snRNAs) and proteins. The interaction and sequential assembly of these components on the pre-mRNA molecule orchestrate the precise excision of introns and ligation of exons. This intricate process is essential for generating functional proteins and plays a significant role in cellular regulation. Alternative splicing, where different combinations of exons are joined, further increases the diversity of proteins that can be produced from a single gene, a process also facilitated by the spliceosome.