To further examine whether ATF3 overexpression affects ion channel genes related to LQTS, quantitative PCR was performed on seven representative genes (kcnq1.1, kcnh2b, cacna1c, calm1a, calm1b, kcnj2a, and kcnj2b) using cardiac cDNA from 4-month post-fertilization (mpf) zebrafish hearts (Fig. 4h). This evidence concerns the gene ATF3 and familial long QT syndrome.