Conditional Smad7 Expression in Embryonic Pdx1 ⁺ Cells Leads to Pancreatic Malformation

<div><p>(A–D) Whole-mounted abdominal organs from E17.5 embryos with the indicated genotypes.</p> <p>(A–C) Views of the pancreas (outlined by dashes) at E17.5 in wild-type and bitransgenic <i>Pdx1-tTA/Smad7</i> mice. (C) shows a magnified view of the pancreatic region marked by the arrow in (B). Adjacent organs marked in (C): St, stomach; Sp, spleen; Du, duodenum. </p> <p>(D) Bitransgenic <i>Pdx1-tTA/Smad7</i> embryos from doxycycline-fed mothers (+ <i>dox</i>) develop a morphologically normal pancreas. </p> <p>(E–L) Smad7 (red) or Pdx1 (green) expression detected by immunohistochemistry in the pancreas of E14.5 mice with the indicated genotypes.</p> <p>(M–O) Immunohistochemical detection of glucagon⁺ (red) and insulin⁺ (green) cells at P1 in mice with the indicated genotypes. </p> <p>(O) Bitransgenic <i>Pdx1-tTA/Smad7</i> embryos from doxycycline-fed mothers (+ <i>dox</i>) develop normal-appearing islets. Original magnification is 4× for (A–D), 63× for (E–H), and 20× for (I–O). </p>