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Synopses of Research Articles Looping Out Introns to Help Splicing Richard Robinson | DOI: 10.1371/journal.pbio.0040041 One of the most surprising discoveries help the splicing machinery remove in molecular biology was that a gene’s the intron. The authors further coding region is broken up into smaller support their model by showing that pieces (the exons) interrupted by splicing could also be stimulated just noncoding portions called introns. by inserting complementary RNA After the DNA is transcribed into RNA, sequences at each end of the intron. and before the RNA can leave the These have the ability to bind to one nucleus, the introns must be cut out another, forming the intron into a and the exons spliced together. DOI: 10.1371/journal.pbio.0040041.g001 loop. Since introns were discovered However, they note that in some Two hnRNP proteins interact to connect in 1977, the details of the splicing introns, only one hnRNP A/B site, the two ends of an intron, forming a loop to operations have been a major object help the cell’s splicing machinery remove positioned on the upstream end, is of study. For sp