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Global analysis of the nuclear processing of transcripts with unspliced U12-type introns by the exosome

U12-type introns are a rare class of introns in the genomes of diverse eukaryotes. In the human genome, they number over 700. A subset of these introns has been shown to be spliced at a slower rate compared to the major U2-type introns. This suggests a rate-limiting regulatory function for the minor...

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Detalles Bibliográficos
Autores principales: Niemelä, Elina H., Oghabian, Ali, Staals, Raymond H.J., Greco, Dario, Pruijn, Ger J.M., Frilander, Mikko J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2014
Materias:
RNA
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4066798/
https://www.ncbi.nlm.nih.gov/pubmed/24848017
http://dx.doi.org/10.1093/nar/gku391
Descripción
Sumario:U12-type introns are a rare class of introns in the genomes of diverse eukaryotes. In the human genome, they number over 700. A subset of these introns has been shown to be spliced at a slower rate compared to the major U2-type introns. This suggests a rate-limiting regulatory function for the minor spliceosome in the processing of transcripts containing U12-type introns. However, both the generality of slower splicing and the subsequent fate of partially processed pre-mRNAs remained unknown. Here, we present a global analysis of the nuclear retention of transcripts containing U12-type introns and provide evidence for the nuclear decay of such transcripts in human cells. Using SOLiD RNA sequencing technology, we find that, in normal cells, U12-type introns are on average 2-fold more retained than the surrounding U2-type introns. Furthermore, we find that knockdown of RRP41 and DIS3 subunits of the exosome stabilizes an overlapping set of U12-type introns. RRP41 knockdown leads to slower decay kinetics of U12-type introns and globally upregulates the retention of U12-type, but not U2-type, introns. Our results indicate that U12-type introns are spliced less efficiently and are targeted by the exosome. These characteristics support their role in the regulation of cellular mRNA levels.