Figure 6. Opposite regulation of admp1 and admp2 by BMP signalling.

(a) admp1 expression is abolished in nodal morphants and following inhibition of Nodal signalling by SB431542. admp1 expression is also suppressed by overexpression of nodal but it is strongly upregulated in nickel treated embryos. (b) Expression of admp1 at gastrula stage in control embryos and following knockdown of various components of the BMP signalling pathway as indicated. Blocking BMP signalling using either a morpholino targeting bmp2/4, or the BMP type I receptor alk3/6, or the BMP type I receptor alk1/2 causes a partial extension of admp1 while blocking translation of both alk3/6 and alk1/2 transcripts with a combination of morpholinos causes a massive extension of admp1 expression to most of the ectoderm. (c) A massive derepression of admp1 is also observed after combining inhibition of bmp2/4 mRNA translation and overexpression of nodal. (d) Expression of admp2 is expanded ventrally following treatment with recombinant BMP4 and suppressed by overexpression of nodal or treatment with nickel. Expression of admp2 persists in a thin layer of dorsal-vegetal cells following inhibition of Nodal signalling by treatment with SB431542. LV, lateral view; VV, vegetal view; FV, frontal view, AV, animal view. Scale bar, 10 μm.