The histone deacetylase (HDAC) inhibitor VPA disrupts ventral progenitor boundaries.

(A-F) Sections taken from E3 embryos treated with the indicated dilutions of VPA at E2 and stained for markers (Olig2, Nkx2.2, and FoxA2) that identify the three normally distinct ventral progenitor domains in the spinal cord. Inset schematic at bottom indicates the three progenitor domain boundaries analyzed and the corresponding markers used. pMN = motoneurons progenitor domain, p3 = V3 interneuron progenitor domain, FP = floor plate domain. Note that the number of double-labeled cells in both boundary regions increases significantly with increasing VPA concentrations (arrowheads) (A, D) controls; (B, E) VPA at 1mM; (C, F) VPA at 100mM). (G) Quantification of the results in A-F. *p<0.001.