Identification of Kv11.1 isoform switch as a novel pathogenic mechanism of long-QT syndrome

Qiuming Gong, Matthew R. Stump, Vivianne Deng, Li Zhang, Zhengfeng Zhou

    Research output: Contribution to journalArticlepeer-review

    5 Scopus citations

    Abstract

    Background: The KCNH2 gene encodes the Kv11.1 potassium channel that conducts the rapidly activating delayed rectifier current in the heart. The relative expression of the full-length Kv11.1a isoform and the C-terminally truncated Kv11.1a-USO isoform plays an important role in regulation of channel function. The formation of C-terminal isoforms is determined by competition between the splicing and alternative polyadenylation of KCNH2 intron 9. It is not known whether changes in the relative expression of Kv11.1a and Kv11.1a-USO can cause long-QT syndrome. Methods and Results: We identified a novel KCNH2 splice site mutation in a large family. The mutation, IVS9-2delA, is a deletion of the A in the AG dinucleotide of the 3' acceptor site of intron 9. We designed an intron-containing full-length KCNH2 gene construct to study the effects of the mutation on the relative expression of Kv11.1a and Kv11.1a-USO at the mRNA, protein, and functional levels. We found that this mutation disrupted normal splicing and resulted in exclusive polyadenylation of intron 9, leading to a switch from the functional Kv11.1a to the nonfunctional Kv11.1a-USO isoform in HEK293 cells and HL-1 cardiomyocytes. We also showed that IVS9-2delA caused isoform switch in the mutant allele of mRNA isolated from patient lymphocytes. Conclusions: Our findings indicate that the IVS9-2delA mutation causes a switch in the expression of the functional Kv11.1a isoform to the nonfunctional Kv11.1a-USO isoform. Kv11.1 isoform switch represents a novel mechanism in the pathogenesis of long-QT syndrome..

    Original languageEnglish (US)
    Pages (from-to)482-490
    Number of pages9
    JournalCirculation: Cardiovascular Genetics
    Volume7
    Issue number4
    DOIs
    StatePublished - Aug 1 2014

    Keywords

    • Long QT syndrome
    • Potassium channels

    ASJC Scopus subject areas

    • Genetics
    • Cardiology and Cardiovascular Medicine
    • Genetics(clinical)

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