Figure 7

Changes in Lhx1,5 and Pax2 expression after Sfrp1 transfection. (a-c') Chicken neural tubes electroporated at HH12-13 with pCAGGS::Phox2b-IRES-EGFP (a, a'), pCAGGS::Sfrp1-IRES-EGFP (b, b') or with pCAGGS::Sfrp1-IRES-EGFP plus pCAGGS::Phox2b-IRES-EGFP (c, c') were analyzed by anti-Lhx1,5 and anti-GFP immunohistochemistry. In (a, b, c), the anti-Lhx1,5 staining is shown alone, and in (a', b', c') it is merged with the anti-GFP immunofluorescence. Phox2b represses Lhx1,5 normally expressed in interneuron populations dI2, dI4, dI6 and V0 (brackets), while Sfrp1 increases the number of Lhx1,5⁺ cells (asterisk) and counteracts Phox2b in its capacity of repressing Lhx1,5 (compare (a) and (c)). (d-f') Chicken neural tubes electroporated at HH12-13 with pCAGGS::Phox2b-IRES-EGFP (d, d'), pCAGGS::Sfrp1-IRES-EGFP (e, e') or with pCAGGS::Sfrp1-IRES-EGFP plus pCAGGS::Phox2b-IRES-EGFP (f, f') were analyzed by anti-GFP immunohistochemistry or by ISH with a Pax2 probe as indicated. Pax2 is down-regulated in all three conditions.