Subtle defects in mRNA and protein expression of putative inhibitory neuronal subtypes in the MePV of Nkx2-1 mutant mice. (A-H) mRNA and protein expression in E18.5 control (A,C,E,G) or Nkx2-1 mutant (B,D,F,H) posterior MeA reveals subtle or no apparent defects in inhibitory neuronal subtypes in the MePV. (A,B) The mRNA expression of Cck does not appear to be altered in Nkx2-1 mutant mice (B, arrow) compared to control (A, arrow). (C,D) Lhx9 mRNA expression, which in controls is found in the MePV (C, arrow) is observed in the mutant MePV (D, arrow), although the expression appears to be weaker. (E,F) Shh mRNA expression, which is found in the control MePV (E, arrow), is maintained in the absence of Nkx2-1, albeit in a reduced expression domain (F, arrow). (G,H) Permanent immunohistochemistry for nNOS shows a large cluster of immunopositive cells in both the control (G, arrow) and mutant MePV (H, arrow), indicating that Nkx2-1 does not play a significant role in specification or maintenance of MePV cell populations. n = 3 for both control and Nkx2-1 mutant for each gene and for nNOS immunohistochemistry. Abbreviations: AMY, amygdala; CTX, cortex; HP, hippocampus; HY, hypothalamus; opt, optic tract; PIR, piriform cortex. Scale bar: 500 μm (A,B); 250 μm (C-F); 300 μm (G,H).