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Figure 7 | Neural Development

Figure 7

From: Sp8 exhibits reciprocal induction with Fgf8 but has an opposing effect on anterior-posterior cortical area patterning

Figure 7

Anterior electroporation of a dominant negative form of Sp8 inhibits endogenous Fgf8 expression in the commissural plate and results in an anterior shift in area patterning. Anterior electroporation of a dominant negative form of Sp8 inhibits endogenous Fgf8 expression in the commissural plate and results in an anterior shift in area patterning. (a-h) Anterior electroporation of a dominant negative form of Sp8 inhibits endogenous Fgf8 expression in the CoP. Electroporation of the Sp8 dominant negative chimeric construct, Sp8-engrailed, suppresses endogenous Fgf8 expression in the CoP (b), as well as expression of Pea3, a downstream target of Fgf8 (f) at E14.5. Fgf8 and Pea3 expression in brains with similar electroporation of the control engrailed construct (a, e) is indistinguishable from non-transfected brains (not shown). Arrowheads indicate Fgf8 (a, b) and Pea3 expression domains (e, f). An EGFP expression construct co-electroporated with Sp8-engrailed and engrailed control constructs are shown in parallel and define the transfection domain (c, d, g, h). (i, j) Anterior ectopic expression of Sp8-engrailed results in an anterior shift of cortical areas. Tangential cortical sections through layer 4 of a P7 brain electroporated at E11.5 with control vector (i) or Sp8-engrailed (j) and processed for serotonin immunostaining to reveal the primary sensory areas: somatosensory (S1), auditory (A1) and visual (V1). In cortex of brains with anterior electroporation of Sp8-engrailed, S1 shifts far anteriorly, resulting in a very small amount of cortex remaining for motor (M) areas. The arrow in (j) indicates putative visual areas. Scale bars: 0.5 mm (a-h), 1.0 mm (i, j). (k) Quantification of motor area size in Sp8-engrailed electroporated brains. The length of motor areas is measured as a ratio of the length from the edge of anterior flattened brains to the staining of S1 regions (ML) and the total length (TL) of serotonin staining of flattened brains. Compared to engrailed control vector cases (28.89 ± 1.35% standard error of the mean (SEM, n = 5), brains electroporated with Sp8-engrailed show shrunken motor areas (13.66 ± 1.34% SEM, n = 6), as indicated in the middle panel. The right panel shows a scatter plot of individual cases.

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