Lives that introns lead after splicing.

摘要: After transcription of a eukaryotic pre-mRNA, its introns are removed by the spliceosome, joining exons for translation. The intron products splicing have long been considered 'junk' and destined only destruction. But because they large in size under weak selection constraints, many evolutionarily repurposed to serve roles after splicing. Some spliced precursors further processing other encoded RNAs such as small nucleolar RNAs, microRNAs, noncoding RNAs. Other half-lives can be exported cytoplasm, suggesting that viruses encode accumulate play important but mysterious viral latency. Turnover most lariat-introns is initiated cleavage their internal 2'-5' phosphodiester bonds unique debranching endonuclease, linear degraded exoribonucleases. However, several appear evade this turnover pathway determinants stability largely unknown. Whereas stable were discovered serendipitously, new experimental computational tools will enable direct identification study. Finally, origins mechanisms mobility mysterious, mechanistic studies life cycle may yield insights into how arose became widespread.