Figure 3.

Armcx3 effects on progenitor proliferation depend on its mitochondrial localization. (A–D,F,H) Representative transverse sections of chick neural tubes from embryos electroporated at HH stage 12 with the indicated plasmids and processed and analyzed 24hpe as described in Figure 1. Overexpressed Arcmx3 is localized at the mitochondria of neural progenitors as indicated by its colocalization with the mitochondrial marker CoxIV. By contrast, a truncated form of Armcx3 which lacks its mitochondrial targeting sequence (Armcx3Δ1-12) displays a cytoplasmic non-mitochondrial localization (A). Arrows in (A) label mitochondria co-localizing with Armcx3 (left panels) but not with the Armcx3Δ(1-12) construct lacking the mitochondrial targeting sequence (right panels). The overexpression of this truncated form neither induced a lateral distribution of progenitors (B,E) nor modified the percentage of Sox2/GFP-positive or HuCD/GFP-positive cells (D–G). Consistently, the non-mitochondrial Armcx3 form did not induce changes in the percentage of GFP/PH3 or GFP/BrdU positive cells (I). Data represent the mean ± s.e.m.