Fig. 6

Long-term tracking of erbb2 myocardial crispants and stable-myocardial mutants demonstrates a cell-autonomous role in trabeculation (A) Representation of the location of the gRNAs targeting erbb2. (B and C) Representative single plane confocal images of embryonic hearts at 4 dpf from wild-type (B) and cardiodeleter+ animals (C), injected with a guide shuttle encoding gRNAs targeting erbb2 (erbb2-gs), immunostained to detect Tnnt2a (cyan). (D and E) Representative heart sections from animals of the indicated genotypes, injected with the erbb2-gs, analyzed at 40 dpf. Magnifications of the boxed areas in D and E are shown in (D′–E′′). Yellow arrowheads, guide shuttle+ cardiomyocytes located at the primordial myocardium; white arrows, guide shuttle+ trabecular cardiomyocytes; asterisks, trabecules. (F and G) Representative images of 4 dpf embryonic hearts from the indicated genotypes, immunostained to detect nGFP (cardiodeleter, green) and mKate (erbb2-gs, magenta). Cyan arrowheads, primordial cardiomyocytes; white arrows, trabecular myocardium. (H and I) Representative sections of cardiodeleter+ (H) and cardiodeleter+erbb2-gs+ siblings (I) stained with the AFOG technique to detect collagen (blue) and myocardium (orange/brown). Whole fish pictures shown on the top, right corner. (H′ and I′) Consecutive sections from the hearts shown in (H) and (I), immunostained to detect nGFP (cardiodeleter, green) and mKate (erbb2-gs, magenta). at, atrium; v, ventricle. Scale bars, 20 μm (B, C, F, and G), 100 μm (D, E, H, and I).