FIGURE 4.

Re1 and Re2 mediate Arx transcription in αTC1–6 cells. A, pGL4.27-Re1, pGL4.27-Re2, and pGL4.27-Re1/2 were transfected into αTC1–6 cells in the presence or absence of a Isl-1-Myc expression plasmid. B, Western blot analysis using Isl-1 and control α-tubulin antibodies demonstrates a ∼70% reduction of Isl-1 protein levels in Isl-1 shRNA lentivirus-treated αTC1–6 cells. C, endogenous Arx mRNA expression was down-regulated relative to HPRT in Isl-1 shRNA treated αTC1–6 cells. D, Isl-1 shRNA knockdown reduced pGL4.27-Re1 and pGL4.27-Re2 reporter activity in αTC1–6 cells. Results are presented as the mean ± S.E. *, p <0.05. pGL4.27-Arx activity was normalized to that of the pRL-SV40 Renilla luciferase in A and D.