Figure 3.

Overexpression of GNC results in increased chloroplast number and expanded zones of chloroplast production. A, Cross-sections of fixed hypocotyls of 7-d-old Col-0, gnc cga1 mutant, OX-1, and OX-2 seedlings grown under constant white light. Bars = 0.01 mm. Arrows indicate chloroplasts in the cortical cells. Arrowheads indicate chloroplasts in the epidermal cells. B, Quantification of chloroplasts in all epidermal cells or outer cortical cells of hypocotyl cross-sections. Cells from three individual hypocotyls of each line were quantified. Error bars indicate sd (Dunnett’s multiple comparison test was performed by using Col-0 of each condition as a reference group after one-way ANOVA [**P < 0.01, ***P < 0.001]). C, Chlorophyll content of hypocotyls from 7-d-old seedlings grown under 100 µmol m⁻² s⁻¹ constant white light. Each sample represents the mean of seven replicates of 10 hypocotyls each. Error bars indicate se (Dunnett’s multiple comparison test was performed by using Col-0 as a reference group after one-way ANOVA [***P < 0.001]). D, RT-PCR and immunoblot analyses showing the levels of GNC transcript and protein. Total RNA extracted from 10-d-old seedlings was used for RT-PCR to examine the transcript of GNC. β-TUBULIN3 (β-TUB 3) was used as the internal control. E, Total protein extracted from 10-d-old seedlings was analyzed by anti-GFP antibodies. α-Tubulin as a loading control was detected by anti-tubulin antibodies.