Fig. 4. Effects of transitin deletions in transfected neuroepithelial cells. Transfected spinal cord was examined 1.5 days after transfection. (A) EGFP transfection does not affect the basal localization of transitin (purple, upper panels) or Numb (purple, lower panels) in mitotic neuroepithelial cells. (B) Overexpression of FLAG-Numb has no effect on transitin localization. (C) Transfection of FLAG-Trans(328-816) increases Numb expression (low magnification in upper panels and high magnification in middle panels). EGFP-F shows a transfected area. No effect on transitin localization was observed (lower panels). (D) Weakly expressed FLAG-Trans(1-327) colocalizes with Numb in the basal cortex (upper panels), whereas high levels of FLAG-Trans(1-327) disrupts Numb localization (lower panels). (E,F) RNAi-mediated depletion of transitin causes a loss of basal Numb crescent. A mixture of EGFP expression vector and double-stranded (ds)RNA corresponding to the transitin gene sequence was electroporated into a developing neural tube. Transfected cells (green) show little staining for anti-transitin (E, outlined). (F) Transfected mitotic neuroepithelium (NE) cells (green) possess little anti-Numb immunoreactivity, whereas untransfected neighboring mitotic cells have apparent basal Numb crescent. Circled areas show individual cells. (A-F) Basal is up, except for low-magnification pictures of spinal cord in C. Blue is DAPI nuclear staining.