Identification Of A Novel GATA6 Mutation Associated With Idiopathic Dilated Cardiomyopathy

Backgrounds: Dilated cardiomyopathy(DCM),predominantly characterized by progressive left ventricular dilation and contractile dysfunction,is the most common type of primary heart muscle disorder,with a prevalence of approximately 1/250 in the general population.DCM is a major cause of heart failure and sudden cardiac death,and also the commonest indication for cardiac transplantation.Recent researches have substantiated that genetic defects are important etiologies for DCM.Objectives: The present study was designed to identify a novel GATA6 mutation associated with idiopathic DCM,and to unveil the molecular mechanism underpinning DCMMethods: In the present study,132 unrelated cases affected with idiopathic DCM aa well as 220 unrelated healthy control persons were recruited.The clinical data and the peripheral venous blood samples were collected.The genomic DNA was isolated with a DNA purification kit.The entire coding regions of the GATA6 gene were amplified by using polymerase chain reaction reagents and the amplified GATA6 fragments were sequenced with a cycle sequencing kit.The obtained sequences were aligned with those of GATA6 derived from the Nucleotide database to identify a GATA6 sequence variation.The databases of American PubMed and SNP and Chinese Wan Fang were retrieved to confirm the novelty of the identified mutation.The online computer softwares of MUSCL and MutationTaster were used to evaluate whether the mutated amino acid was conserved evolutionarily and whether the mutation was causative,respectively.The wild-type GATA6 was cloned,and the expression plasmid of GATA6-pcDNA3.1 was constructed.The mutant GATA6-pcDNA3.1 was produced by site-directed mutagenesis.Transfections of various plasmids into tool cells were performed with lipofectamine reagent.The transcriptional activation function of the mutant GATA6 was analyzed in contrast to its wild-type counterpart with a dual-luciferase reporter assay kit.Results: A novel heterozygous GATA6 mutation,c.1165G>C,equivalent to p.E389 X,was identified in a sporadic DCM patient.The nonsense mutation was not detected in the 220 control people.The nonsense mutation was not reported in the databases of American PubMed and SNP and Chinese Wan Fang.The amino acid altered by the mutation was evolutionarily conserved,and the mutation was predicted to be pathogenic.The dual-luciferase reporter assays revealed that the E389X-mutant GATA6 lost the ability to transcriptionally activate the ANF promoter.Conclusion: This study firstly reports on the association of a novel GATA6 mutation with sporadic DCM,expanding the mutational spectrum of GATA6 linked to DCM,and reveals a novel molecular mechanism of DCM.