Evolutionary dynamics of U12-type spliceosomal introns

dc.contributor.authorLin, Chiao-Feng
dc.contributor.authorMount, Stephen M
dc.contributor.authorJarmołowski, Artur
dc.contributor.authorMakałowski, Wojciech
dc.date.accessioned2021-11-15T21:09:25Z
dc.date.available2021-11-15T21:09:25Z
dc.date.issued2010-02-17
dc.description.abstractMany multicellular eukaryotes have two types of spliceosomes for the removal of introns from messenger RNA precursors. The major (U2) spliceosome processes the vast majority of introns, referred to as U2-type introns, while the minor (U12) spliceosome removes a small fraction (less than 0.5%) of introns, referred to as U12-type introns. U12-type introns have distinct sequence elements and usually occur together in genes with U2-type introns. A phylogenetic distribution of U12-type introns shows that the minor splicing pathway appeared very early in eukaryotic evolution and has been lost repeatedly. We have investigated the evolution of U12-type introns among eighteen metazoan genomes by analyzing orthologous U12-type intron clusters. Examination of gain, loss, and type switching shows that intron type is remarkably conserved among vertebrates. Among 180 intron clusters, only eight show intron loss in any vertebrate species and only five show conversion between the U12 and the U2-type. Although there are only nineteen U12-type introns in Drosophila melanogaster, we found one case of U2 to U12-type conversion, apparently mediated by the activation of cryptic U12 splice sites early in the dipteran lineage. Overall, loss of U12-type introns is more common than conversion to U2-type and the U12 to U2 conversion occurs more frequently among introns of the GT-AG subtype than among introns of the AT-AC subtype. We also found support for natural U12-type introns with non-canonical terminal dinucleotides (CT-AC, GG-AG, and GA-AG) that have not been previously reported. Although complete loss of the U12-type spliceosome has occurred repeatedly, U12 introns are extremely stable in some taxa, including eutheria. Loss of U12 introns or the genes containing them is more common than conversion to the U2-type. The degeneracy of U12-type terminal dinucleotides among natural U12-type introns is higher than previously thought.en_US
dc.description.urihttps://doi.org/10.1186/1471-2148-10-47
dc.identifierhttps://doi.org/10.13016/wzen-mzii
dc.identifier.citationLin, CF., Mount, S.M., Jarmołowski, A. et al. Evolutionary dynamics of U12-type spliceosomal introns. BMC Evol Biol 10, 47 (2010).en_US
dc.identifier.urihttp://hdl.handle.net/1903/28120
dc.language.isoen_USen_US
dc.publisherSpringer Natureen_US
dc.relation.isAvailableAtCell Biology & Molecular Geneticsen_us
dc.relation.isAvailableAtDigital Repository at the University of Marylanden_us
dc.relation.isAvailableAtCollege of Computer, Mathematical & Natural Sciencesen_us
dc.relation.isAvailableAtUniversity of Maryland (College Park, MD)en_us
dc.subjectSplice Siteen_US
dc.subjectIntron Lossen_US
dc.subjectIntron Gainen_US
dc.subjectMonodelphis Domesticaen_US
dc.subjectSplice Systemen_US
dc.titleEvolutionary dynamics of U12-type spliceosomal intronsen_US
dc.typeArticleen_US

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