<i>Myh6</i>^{<i>MerCreMer/+</i>} introduces specific recombination in cardiomyocytes.

<p><i>R26R</i>^{<i>tdTomato/+</i>} reporter line was used to trace <i>Myh6</i> lineage after tamoxifen induction. <b>(A)</b> tdTomato expression on the whole-mount hearts at E13.5-P60. <b>(B-I)</b> Immunostaining on transverse sections of hearts revealed tdTomato expression was co-localized with Tnnt2 (B-E), but was not co-localized with αSMA (F,G) or PECAM (H,I). Notched arrows in B2/C2/D2/E2 indicate tdTomato expression. Arrowheads in B2/C2 indicate lower level expression of tdTomato in VS and ventricular wall. Unnotched arrows in F,G indicate αSMA staining, and in H,I indicate PECAM staining. Arrowheads in C4 indicate valves. B4-G4 are merged images for B1/2/3-G1/2/3, respectively. H2 and I2 are merged images of H1 and I1 with corresponding tdTomato/DAPI images.