Figure 7

Induction of the early nephrogenic transcription factors and other genes in animal caps. osr1, osr2, hnf1b and lhx1 are induced already after 1.5 hours treatment with activin A (ActA) and retinoic acid (RA) suggesting that they are direct targets, whereas pax8 is first expressed after thirteen hours implying an indirect activation. osr2 and lhx1 (highlighted in grey) are induced after three hours by activin A alone. HNF1B overexpressed in animal caps induces after seven hours osr1, osr2, hnf1a, hnf4a, wnt11b, gdnf and tfe3. After fourteen hours pax2 and esd are increased and rbms1, fgfr4c and gsc are decreased suggesting secondary effects. HNF1B induces the expression of lhx1 by an HNF1 binding site in its promoter region (arrow). Furthermore, the lhx1 target genes cer1 and chrd are induced in HNF1B injected animal caps possibly via lhx1.