(a) Schematic of Drosophila eIF2α kinases. Amino acid deprivation or endoplasmic reticulum (ER) stress activate either GCN2 or PERK, respectively. Both kinases dimerize and phosphorylate eIF2α. (b-d) Representative images of 2–3 day old CVα KD (b), CVα, GCN2 KD (c), and CVα, PERK KD (d) germaria. (e-g) Representative images of 1 day old CVα KD, PERK–/+
(e), CVα KD, PERK–/–(f), and CVα KD, PERK–/–, UAS-PERKK671R
(g) germaria. (h) Phenotypic characterization and quantification of germline differentiation stage in germaria of (e-g). Number of germaria scored above each bar and were studied from 10 or more ovaries, obtained in at least three independent experiments and over two or more crosses. (i-l) Representative images of 2–3 day old CVα KD (i), CVα, PERK KD (j), CVα KD, PERK–/+
(k) and CVα KD, PERK–/–(l) germaria. All RNAi were driven by nos-GAL4. Images are representative of over 100 ovarioles and three independent experiments. Scale bars represent 10 μm. White-dashed line indicates the germline cells. For exact genotypes see S2 Table.