Figure 2.

The Hand1-reporter transgene recapitulates Hand1 expression in the SNS both prenatally and postnatally. A–C, Transverse sections of representative X-gal-stained E10.5 embryos from two independent transgenic lines, termed Line E (B) and Line H (C), show robust transgene expression in SNS progenitors (arrowheads), comparable to control Hand1^lacZ embryos (A). D–I, Whole-mount preparations of X-gal-stained transgenic mice at P0 (E, F), and P21 (H, I) confirm that reporter expression persists in both lines in a manner comparable to that of age-matched Hand1^lacZ mice (D and G, respectively).