(A–D) Zfh1-knockdown (KD) in lamina progenitor cells (LPCs) significantly reduces Zfh1 expression in all LPCs and lamina neurons at 12 hr after pupa formation (APF). The white line circle outlines LPCs. The yellow line circle outlines lamina neurons. White dash circle outlines Zfh1+ glia. Scale bar here and below, 10 µm. Genotype: R27G05-Gal4>UAS-Zfh1-RNAi. Quantification: Zfh1 signal of three cell bodies from each brain and normalized Zfh1 signal by setting the highest Zfh1 signal as 100. (E–H) The total number of Ap+ and Pdm3+ cell bodies is decreased when knocking down Zfh1 in LPCs. The number of Bsh+ L4 and L5 neurons is decreased when knocking down Zfh1 in LPCs. Scale bar, 10 µm. (G) The total number of Ap+ and Pdm3+ cell bodies in a single slice. (H) The number of Bsh+ L4 and L5 neurons in a single slice. Genotype: R27G05-Gal4>UAS-Zfh1-RNAi. (I–K) The number of lamina neurons is decreased when knocking down Zfh1 in LPCs. Scale bar, 10 µm. (K) The number of Elav+ cells in a single slice. Genotype: R27G05-Gal4>UAS-Zfh1-RNAi. (L–N) Zfh1 is ectopically expressed in GFP+ neurons. GFP (Bsh-LexA>LexAop-myrGFP) labels LPCs and L5 neurons in control. The white line circle outlines GFP+ neurons. GFP+ LPCs are Tll+ (yellow arrowhead). Scale bar, 10 µm. (N) The percentage of Zfh1+ cells in GFP+ neurons (Elav+) in control (L) and Bsh-KD (M). We divided GFP+ neurons into three domains with equal width from newborn to older neurons. Data are presented as mean ± SEM. Each dot represents a brain. n=5 brains per genotype. **p<0.01, ***p<0.001, unpaired t-test.