Figure 5.

Tis21-retrovirus inhibits the deregulated proliferation of dentate gyrus progenitor cells and rescues the defective terminal differentiation of Tis21-null neurons. (A) Scheme of retrovirus infection timeline, structure, and injection area. (B) Representative confocal images (40× magnification) of coronal sections of the dentate gyrus, labeled with Hoechst 33258, Ki67 and with GFP, 5 days after infection with either GFP-Tis21 or GFP-empty retroviruses. Scale bars, 50 μm. The white arrowheads indicate cells positive for both GFP and Ki67, white arrows cells positive only for GFP. (C) Percentage ratio between GFP⁺Ki67⁺ cells and the total number of infected cells (GFP⁺), from the analysis of Tis21 knockout dentate gyrus infected with either GFP-Tis21 or GFP-empty virus. The percentage of dividing cells (Ki67⁺) is reduced by the Tis21 virus, relative to the empty virus infections. *p < 0.05 vs. cells infected with GFP-empty virus; Mann-Withney U test. (D) Representative confocal images of dentate gyrus cells triple labeled with Calretinin, NeuN and GFP, 5 days after infection with either GFP-Tis21 or GFP-empty retroviruses. Scale bars, 50 μm. White arrows indicate infected terminally differentiated neurons (GFP⁺Calretinin⁻NeuN⁺); arrowheads indicate infected stage 5 immature neurons (GFP⁺Calretinin⁺NeuN⁺). (E) Percentage ratio between stage 5 immature neurons (GFP⁺stage 5) or stage 6 terminally differentiated neurons (GFP⁺stage 6) and the total number of infected cells (GFP⁺), analyzed in Tis21 knockout dentate gyrus infected with either GFP-Tis21 or GFP-empty virus. The percentages of stage 5 and stage 6 neurons infected with empty virus are significantly decreased or increased, respectively, by the Tis21-expressing virus. *p < 0.05 or ***p < 0.001 vs. cells infected with GFP-empty virus; Mann-Withney U test. (C,E) Cell ratios in the dentate gyrus are mean% ± SEM of the analysis of three animals per group.