RNA Splicing- Definition, process, mechanism, types, errors, uses


RNA splicing is a process in molecular biology that transforms a newly-made precursor messenger RNA (pre-mRNA) transcript into a mature messenger RNA (mRNA) that can be translated into a protein. RNA splicing works by removing all the introns (non-coding regions of RNA) and splicing back together exons (coding regions).

RNA splicing is essential for gene expression and protein diversity in eukaryotic cells, where most genes contain introns that interrupt the coding sequences. RNA splicing occurs in the nucleus either during or immediately after transcription. For nuclear-encoded genes, splicing is usually required to create an mRNA molecule that can be exported to the cytoplasm and recognized by the ribosomes.

RNA splicing is catalyzed by a large and complex molecule called the spliceosome, which consists of five small nuclear RNAs (snRNAs) and about 80 protein molecules. The spliceosome recognizes the splice sites at the 5` and 3` ends of the introns and performs two transesterification reactions that result in the excision of the intron and the ligation of the exons.

Besides the spliceosome-mediated splicing, there are other types of RNA splicing that occur in nature, such as self-splicing and tRNA splicing. Self-splicing is a type of RNA splicing that occurs in some rare introns that can catalyze their own removal from the pre-mRNA without the help of other proteins or spliceosomes. tRNA splicing is a type of RNA splicing that occurs in tRNA genes that are interrupted by introns, but involves a different mechanism and enzymes than spliceosomal splicing.

Another important aspect of RNA splicing is alternative splicing, which is a process that allows a single pre-mRNA to be spliced in different ways, resulting in multiple mRNA variants that encode different proteins. Alternative splicing is a major source of protein diversity and complexity in eukaryotic cells, and it also plays a vital role in cellular differentiation and organism development.

RNA splicing is a highly regulated and precise process that affects many biological functions and pathways. However, errors or mutations in RNA splicing can lead to various diseases, such as cancer, neurodegenerative disorders, and genetic syndromes.