A novel type of splicing enhancer regulating adenovirus pre-mRNA splicing
2000 (English)In: Molecular and Cellular Biology, ISSN 0270-7306, E-ISSN 1098-5549, Vol. 20, no 7, 2317-2325 p.Article in journal (Refereed) Published
Splicing of the adenovirus IIIa pre-mRNA is subjected to a temporal regulation, such that efficient IIIa 3' splice site usage is confined to the late phase of the infectious cycle. Here we show that IIIa pre-mRNA splicing is activated more than 200-fold in nuclear extracts prepared from late adenovirus-infected cells (Ad-NE) compared to uninfected HeLa cell nuclear extracts (HeLa-NE). In contrast, splicing of the beta-globin pre-mRNA is repressed in Ad-NE. We constructed hybrid pre-mRNAs between IIIa and beta-globin in order to identify the minimal IIIa sequence element conferring enhanced splicing in Ad-NE. Using this approach, we show that the IIIa branch site/pyrimidine tract functions as a Janus element: it blocks splicing in HeLa-NE and functions as a splicing enhancer in Ad-NE. Therefore, we named this sequence the IIIa virus infection-dependent splicing enhancer (3VDE). This element is essential for regulated IIIa pre-mRNA splicing in Ad-NE and sufficient to confer an enhanced splicing phenotype to the beta-globin pre-mRNA in Ad-NE. We further show that the increase in IIIa splicing observed in Ad-NE is not accompanied by a similar increase in U2AF binding to the IIIa pyrimidine tract. This finding suggests that splicing activation by the 3VDE may operate without efficient U2AF interaction with the pre-mRNA. Importantly, this report represents the first description of a splicing enhancer that has evolved to function selectively in the context of a virus infection, a finding that adds a new level at which viruses may subvert the host cell RNA biosynthetic machinery to facilitate their own replication.
Place, publisher, year, edition, pages
2000. Vol. 20, no 7, 2317-2325 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-52395ISI: 000085809200003PubMedID: 10713155OAI: oai:DiVA.org:uu-52395DiVA: diva2:80304