Fig. 7

Fig. 7 Bmpr2a and bmpr2b regulate asymmetric expression of the left-specific genes lefty2, lefty1, spaw and pitx2 in the lateral plate mesoderm (LPM) and of bmp4 in the left heart field. (A) lefty2 is expressed at the 25-somite stage in the left heart field in wild type embryos. (B–E) Expression of lefty2 in bmpr2aMO3-, bmpr2bMO3- or bmpr2a/bmpr2bMO3-injected embryos (representative pictures, see Table 4). (F) lefty1 is expressed in the posterior notochord and left heart field at 22 somites. Bmpr2a-, bmpr2b- and double bmpr2a/bmpr2b morphants show normal (G), absent (H), bilateral (I) or right-sided (J) lefty1 expression in the heart field. (K) At 14–16 somites, spaw is expressed in the left LPM (arrowheads) while ntl expression marks the midline. (L–O) MO-induced knockdown of bmpr2a, bmpr2b or bmpr2a/bmpr2b (see Table 4) resulted in left (L), absent (M), bilateral (N) or rightward (O) spaw expression in the LPM. (P) In wild type embryos pitx2 is expressed in the left LPM. Bmpr2a, bmpr2b or bmpr2a/bmpr2b morphants display left-sided (Q), absent (R), bilateral (S) or reversed (T) pitx2 expression (arrowheads). (U) At 22 somites, bmp4 expression is higher in the left heart field. Bmpr2a, bmpr2b or bmpr2a/bmpr2b morphants display normal (V), symmetric (W) or reversed asymmetric bmp4 expression (X). (A–X) Dorsal view, anterior to the top. L, left, A, absent, B, bilateral, R, right.