Drug-sensitized zebrafish screen identifies multiple genes, including GINS3, as regulators of myocardial repolarization.
BACKGROUND
Cardiac repolarization, the process by which cardiomyocytes return to their resting potential after each beat, is a highly regulated process that is critical for heart rhythm stability. Perturbations of cardiac repolarization increase the risk for life-threatening arrhythmias and sudden cardiac death. Although genetic studies of familial long-QT syndromes have uncovered several key genes in cardiac repolarization, the major heritable contribution to this trait remains unexplained. Identification of additional genes may lead to a better understanding of the underlying biology, aid in identification of patients at risk for sudden death, and potentially enable new treatments for susceptible individuals.


RESULTS
We extended and refined a zebrafish model of cardiac repolarization by using fluorescent reporters of transmembrane potential. We then conducted a drug-sensitized genetic screen in zebrafish, identifying 15 genes, including GINS3, that affect cardiac repolarization. Testing these genes for human relevance in 2 concurrently completed genome-wide association studies revealed that the human GINS3 ortholog is located in the 16q21 locus, which is strongly associated with QT interval.


CONCLUSIONS
This sensitized zebrafish screen identified 15 novel myocardial repolarization genes. Among these genes is GINS3, the human ortholog of which is a major locus in 2 concurrent human genome-wide association studies of QT interval. These results reveal a novel network of genes that regulate cardiac repolarization.
Milan
David J
DJ
Cardiovascular Research Center, and Cardiology Division, Massachusetts General Hospital, Boston, USA. dmilan@partners.org
Kim
Albert M
AM
Winterfield
Jeffrey R
JR
Jones
Ian L
IL
Pfeufer
Arne
A
Sanna
Serena
S
Arking
Dan E
DE
Amsterdam
Adam H
AH
Sabeh
Khaled M
KM
Mably
John D
JD
Rosenbaum
David S
DS
Peterson
Randall T
RT
Chakravarti
Aravinda
A
Kääb
Stefan
S
Roden
Dan M
DM
MacRae
Calum A
CA
D000818:Animals; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D020869:Gene Expression Profiling; D005809:Genes, Regulator / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008133:Long QT Syndrome / Q000235:genetics; D008564:Membrane Potentials / Q000502:physiology*; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology / Q000502:physiology; D010641:Phenotype; D012307:Risk Factors; D015027:Zebrafish