Fig. 3. Expression of Cm-derrière disturbs left–right asymmetry. (A) Embryos were injected with 250 pg of Cm-derrière mRNA or 250 pg of Cm-derrière mRNA plus 50 pg of WT derrière mRNA in L2 or L3 at 16-cell stage. Expression of Cm-derrière altered the orientation of cardiac looping (16% L2, SD = 4.6%; N = 120; 23% L3, SD = 7.8%; N = 118), and co-injection of WT derrière rescued completely the alteration of cardiac orientation induced by Cm-derrière (0% L2; N = 35; 0% L3; N = 42). (B) Xnr-1 expression patterns in Cm-derrière-injected embryos. The percentages of cases of indicated Xnr-1 expression in Cm-derrière L2 injected (blue, N = 44), Cm-derrière L3 injected (yellow, N = 42), Cm-derrière R3 injected (orange, N = 22) and uninjected (green, N = 32) embryos are shown.