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Published on: March 12, 2013
Dissection of a quantitative trait locus for PR interval duration identifies Tnni3k as a novel modulator of cardiac
Elisabeth M Lodder1, Brendon P Scicluna, Annalisa Milano
1Heart Failure Research Center, Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Plos Genetics
|December 14, 2012
Summary
Scientists identified Tnni3k as a gene influencing heart rhythm. This discovery sheds light on the genetic basis of atrio-ventricular conduction and may help understand sudden cardiac death risks.
Area of Science:
- Cardiovascular Genetics
- Molecular Cardiology
- Electrophysiology
Background:
- Atrio-ventricular conduction disease, marked by prolonged PR interval on ECG, is linked to Mendelian rhythm disorders and sudden cardiac death.
- PR interval prolongation predicts atrial fibrillation, a common arrhythmia, yet its genetic regulators are poorly understood.
- Previous studies mapped a quantitative trait locus (QTL) for PR interval duration in mice.
Purpose of the Study:
- To identify the specific gene responsible for the PR interval duration QTL in mice.
- To investigate the role of Tnni3k in regulating atrio-ventricular conduction.
Main Methods:
- Genome-wide transcriptional profiling of myocardial tissue from 109 F2 mice.
- Mapping of expression QTLs (eQTLs) and correlation analysis with PR interval duration.
- Genotype analysis and PR interval measurements in various inbred mouse strains, including genetically modified mice.
Main Results:
- Tnni3k was identified as the sole eQTL within the PR interval QTL region, exhibiting cardiac-specific expression and correlating with PR duration.
- Multiple Tnni3k haplotypes exist across mouse strains, with higher mRNA levels associated with longer PR intervals.
- Overexpression of Tnni3k in mice led to a prolonged PR interval.
Conclusions:
- Tnni3k plays a significant role in controlling the electrocardiographic PR interval.
- This finding provides the first evidence linking Tnni3k to atrio-ventricular conduction regulation.
- Tnni3k is a potential target for understanding and managing cardiac conduction disorders.
