Fig. 6. Ectopic activation of Lhx6-GFP reporter expression by Nkx2.1. (A-C) In mouse embryo slice cultures maintained from E13.5+1DIV, no expression of GFP is detected when p5'-Lhx6-GFP is introduced into the wt LGE (arrowhead) or lateral cortex (arrow). (D-F) Ectopically expressed NKX2.1 drives Lhx6-reporter expression in these regions. (G-I) This activation is not present in response to ectopic expression of an altered NKX2.1 construct containing a missense point mutation in the homeodomain that abrogates its ability to bind DNA (Krude et al., 2002). Note that the red signal in G and I is NKX2.1 immunofluorescence that is not affected by the point mutation. (J-L) Co-electroporation of pNkx2.1 and the Lhx6 promoter reporter construct that lacks the NKX2.1 consensus binding sequence (p5'-Lhx6-GFP) results in little expression of GFP. (M-O) As with Nkx2.1 cDNA, fusion of the VP16 activator domain to Nkx2.1 strongly induces the reporter GFP expression in wt LGE or cerebral cortex. In this case, there is reduced detection of the altered NKX2.1 protein by immunofluorescence (M,O). MGE, medial ganglionic eminence; LGE, lateral ganglionic eminence; Ctx, cerebral cortex. Scale bar: 200 µm in A for A-O.