No significant increase in endogenous Pax9 expression was detected in the pellets of AF cells infected with shPax1-a or shPax1-b lentivirus (Supplementary Fig. 2), suggesting that a compensatory increase in endogenous Pax9 does not occur upon knock-down of Pax1 in AF cells. This evidence concerns the gene PAX9 and atrial fibrillation.