The spliceosome is a complex molecular machine found in the cells of eukaryotes, responsible for the process of RNA splicing. During gene expression, it removes non-coding regions called introns from the precursor messenger RNA (pre-mRNA) and joins the coding regions, known as exons, together. This process is essential for producing mature mRNA that can be translated into proteins. The spliceosome is composed of small nuclear ribonucleoproteins (snRNPs) and various proteins that work together to recognize specific sequences at the boundaries of introns and exons. By accurately splicing pre-mRNA, the spliceosome plays a crucial role in gene regulation and the diversity of proteins produced in an organism.