Atrial cardiomyocyte‐specific expression of Cre recombinase driven by an Nppa gene fragment

To study the development of the atria, we produced a transgenic mouse line that expresses Cre under the regulatory control of a 7 kbp fragment of the Natriuretic peptide precursor type A gene (Nppa), from -3 kbp to +4 kbp relative to the transcription start site. Crossing this line with the R26R and Z/EG reporter lines revealed recombinase activity specifically in the cardiomyocytes of the atria and to a lesser extent the inflow tract from E10.5 onwards. At E14.5 recombination in the atria is almost complete. No recombination was observed outside the heart. These mice provide a tool to study gene function in the atria.