Figure 4.

Tlx can regulate the activity of mouse Pax2 promoter in ovo. A mouse Pax2 promoter fused to β-galactosidase (β-gal) construct was introduced alone or in conjunction with pCAGGS-Tlx and pCAGGS-Tlx-VP into the optic vesicles of stage (st.) 9 chick embryos by electroporation. Embryos were stained for β-gal after 24 hrs. (A) Schematic of placement of DNA solution (blue dye) and electrodes for introduction of DNA (Left). Codelivery of GFP allows easy assessment of the targeting efficiency (Right). (B) Pax2-lacZ results in positive β-gal staining in ventral retina (arrow). (C) The addition of Tlx (or Tlx-EnR, not shown) results in suppression of Pax2-lacZ activity. (D) Tlx-VP promotes strong ectopic Pax2-lacZ activity in dorsal retina and diencephalon (arrows).