Bmp2a is required for PhR specification. (A-D) Expression of bmp2a in the wild-type pineal at 14, 16, 18 and 20 hours. (E-H′) Activation of the BMP pathway as judged by labeling with an α-PSmad 1/5/8 antibody shown on confocal projections. The presumptive pineal territory is delineated by GFP expression from the Tg(flh:gfp) transgenic line (Concha et al., 2003). Anterior is upwards. Scale bars: 16 μm. (I-O) Average numbers of Isl1+ neurons, Tg(AANAT2:GFP)+, FRet43+, HuC/D+, Tg(HuC:GFP)+, Isl1+/Pax6+ and lhx3+ cells per pineal gland at 48 hours in control, bmp2a and smad5 morpholino-injected embryos. The number (n) of embryos analyzed is noted for each case. Error bars represent s.d. **P<0.001, ***P<0.0005 using a t-test.
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