Figure 9
Ectopic expression of Sp8 and a dominant active form of Sp8 induce area shifts that oppose Fgf8. (a, b) Ectopic expression of Sp8 (b) at an anterior site of E11.5 brains causes anterior area shifts with a substantial reduction of motor (M) areas compared to control electroporated brains (a) that are indistinguishable from wild type (not shown). Areas of tangential section at P7 cortices are visualized by serotonin immunostaining. (c, d) Anterior ectopic expression of a dominant active form of Sp8, Sp8-VP16 (d), but not theVP16 domain alone (c), induces anterior area shifts similar to Sp8. The dashed line is at the E1 barrel position of control brain for the A-P comparison. (e) Quantification of motor areas in Sp8-, Sp8-VP16, or control-transfected brains. Anterior electroporation of either Sp8 or Sp8-VP16 causes reduction of the motor areas ratio (Sp8, 18.07 ± 1.52% SEM, n = 10; Sp8-VP16, 19.12 ± 2.18% SEM, n = 9), compared to the control cases (control vector; 29.05 ± 0.691%, SEM, n = 5; VP16, 26.88 ± 0.853%, SEM, n = 5). The right panel shows a scatter plot of individual cases. (f-i) Posterior ectopic expression of Sp8 and Sp8-VP16 induces posterior cortical area shifts. Sp8 (g) and Sp8-VP16 (i) ectopic expression at posterior sites causes a posterior shift in area patterning with a reduction in size of V1 areas, whereas expression of an empty vector (F) or the VP16 domain alone (H) has no effect on area patterning. The dashed line is at the A1 barrel position of control brain. Scale bar: 1.0 mm. (l) Quantification of caudal areas in Sp8-, Sp8-VP16, or control-transfected brains. Posterior electroporation of either Sp8 or Sp8-VP16 causes reduction of caudal area ratio (Sp8, 24.42 ± 2.03%, SEM, n = 6; Sp8-VP16, 24.89 ± 0.700% SEM, n = 18), compared to the control cases (control vector, 33.02 ± 0.581%, SEM, n = 5; VP16, 31.16 ± 0.430%, SEM, n = 5). The right panel shows a scatter plot of individual cases. EP, electroporation; ML, motor length; CL, caudal length;TL, total length.