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Identification of the modulators of cardiac ion channel function

Thesis (MScMedSc (Biomedical Sciences. Molecular Biology and Human Genetics))--University of Stellenbosch, 2009. / The human ether-à-go-go-related gene (HERG) encodes the protein underlying the
cardiac potassium current IKr. Mutations in HERG may produce defective channels and
cause Long QT Syndrome (LQTS), a cardiac disease affecting 1 in 2500 people. The
disease is characterised by a prolonged QT interval on a surface electrocardiogram and
has a symptomatic variability of sudden cardiac death in childhood to asymptomatic
longevity. We hypothesised that genetic variation in the proteins that interact with HERG
might modify the clinical expression of LQTS. Yeast two-hybrid methodology was used
to screen a human cardiac cDNA library in order to identify putative HERG N-terminus
ligands. Successive selection stages reduced the number of putative HERG ligandcontaining
colonies (preys) from 268 to 8. Putative prey ligands were sequenced and
identified by BLAST-search. False positive ligands were excluded based on their
function and subcellular location. Three strong candidate ligands were identified: Rhoassociated
coiled-coil containing kinase 1 (ROCK1), γ-sarcoglycan (SGCG) and
microtubule-associated protein 1A (MAP1A). In vitro co-immunoprecipitation (Co-IP)
and mammalian two-hybrid (M2H) analyses were used to validate these proposed
interactions, but failed to do so. This should be further investigated. Analysis of
confirmed interactions will shed light on their functional role and might contribute to
understanding the symptomatic variability seen in LQTS.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2163
Date03 1900
CreatorsCarstens, Johanna J.
ContributorsCorfield, Valerie A., Durrheim, Glenda A., University of Stellenbosch. Faculty of Health Sciences. Dept. of Biomedical Sciences. Molecular Biology and Human Genetics.
PublisherStellenbosch : University of Stellenbosch
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
RightsUniversity of Stellenbosch

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