The 638/+70 bp rat Nppa regulatory region sequence, containing the promoter and silencer and enhancer sequences, is placed upstream of a beta-globin/IgG chimeric intron, nls sequence, the lacZ beta-galactosidase gene and bovine GH poly(A) signal sequence. The regulatory sequence drives expression in the embryonic atrial and ventricular chamber myocardium. (J:76656)