The article discusses the life cycle of spliceosomal small nuclear RNPs (snRNPs) and their role in pre-mRNA splicing. It outlines the biogenesis of snRNPs, including transcription, processing, nuclear export, Cajal bodies, and RNP quality control. The SMN complex is highlighted as a key regulator of cytoplasmic snRNP assembly. The article also explores the nuclear import of snRNPs, RNP remodelling, and the formation of the spliceosome. Spliceosome assembly involves multiple steps, including the recognition of splice sites, the formation of the spliceosome complex, and the catalytic steps of splicing. The article emphasizes the role of RNA in splicing, the regulation of splicing by cis-acting elements, and the influence of splicing factors on splicing decisions. It also discusses the implications of splicing defects in human diseases, such as spinal muscular atrophy and retinitis pigmentosa. The article concludes with a discussion of the splicing code and the challenges in understanding the complex mechanisms of splicing.The article discusses the life cycle of spliceosomal small nuclear RNPs (snRNPs) and their role in pre-mRNA splicing. It outlines the biogenesis of snRNPs, including transcription, processing, nuclear export, Cajal bodies, and RNP quality control. The SMN complex is highlighted as a key regulator of cytoplasmic snRNP assembly. The article also explores the nuclear import of snRNPs, RNP remodelling, and the formation of the spliceosome. Spliceosome assembly involves multiple steps, including the recognition of splice sites, the formation of the spliceosome complex, and the catalytic steps of splicing. The article emphasizes the role of RNA in splicing, the regulation of splicing by cis-acting elements, and the influence of splicing factors on splicing decisions. It also discusses the implications of splicing defects in human diseases, such as spinal muscular atrophy and retinitis pigmentosa. The article concludes with a discussion of the splicing code and the challenges in understanding the complex mechanisms of splicing.