Fig. 4.

The transcriptional activation domain (aristaless domain) of Arx is required for induction of Nkx2.2. A) The schematic diagram depicts a full length Arx (top; rectangle) with the color-coded functional domains (e.g. NLS: nuclear localization signal), and Arx deletion mutants (bottom; lines) with beginning and ending amino acids indicated with numeric numbers (321–470 indicates the Arx fragment containing homeodomain used in Fig 3D). B) Electroporation of Arx or Arx deletion constructs to the chick spinal cords. Green fluorescence is an indicator of electroporated cells and Nkx2.2 immunostaining is shown in red. ArxMT means non-DNA bound homeodomain mutant (R332H). The arrows indicate examples of where Nkx2.2 induction was observed. Note that Arx 1–470 shows no Nkx2.2 induction. Scale bar is 50 μm for all images.