Despite our observation that DNA SSB was increased in cardiomyocytes after TAC operation, we found that the level of protein poly(ADP-ribosylation), which is induced by PARP1/2 as an initial process of SSB repair13, and the expression levels of SSB repair-related genes were rather decreased in the TAC-operated heart (Fig. 1g-i). This evidence concerns the gene PARP1 and persistent truncus arteriosus.