Lipid droplets are mainly localized in dRPCs and are increased by <i>dFatp</i> overexpression in <i>Drosophila</i> retinas.

(A) TEM of ommatidia from one-day-old flies expressing UAS-LacZ (control) or UAS-dFatp under control of the pan-retinal (GMR-Gal4) or dRPC-specific (54C-Gal4) drivers. One ommatidium in each panel shows seven photoreceptors (false colored green) with central rhabdomeres surrounded by dRPCs (false colored pink). Lipid droplets are mainly located in dRPCs (black arrowheads) but can also be observed in photoreceptors (black arrows). Lipid droplet size was increased by dFatp overexpression (b, d, d’) compared to control conditions (a, c, c’). Scale bars, 2 μm (a–d), 1 μm (c’, d’). m, mitochondria; R rhabdomeres. (B) Quantification of lipid droplet density (number per surface area) in dRPCs and photoreceptors in flies with dRPC-specific expression (54C-Gal4) of UAS-LacZ (control), UAS-dFatp, or UAS-Bmm-lipase. Means ± SD of n = 4 eyes. (C) Quantification of lipid droplet size (area in m2) in dRPCs of flies with dRPC-specific (54C-Gal4) expression of UAS-LacZ (control) or UAS-dFatp. (D) Mitochondrial size (area in m2) in photoreceptors of flies with dRPC-specific expression of UAS-LacZ (control) or UAS-dFatp. The boxes represent the median and lower and upper quartiles, and the whiskers represent the 1.5 interquartile range. N = 4 to 5 flies, from which we analyzed >150 fields of view. Log adjusted values: *p<0.05, ***p<0.001 by Tukey’s HSD paired sample comparison tests.