Fig. 10: The role of dGRASP in intestinal lipid absorption and whole-body TG storage in adult flies.

The dGrasp-null mutant allele (dGrasp^−/−), also known as dGrasp³⁰², harbors a deletion of the whole dGrasp coding region. a, b Lipid accumulation in enterocytes of posterior midguts of dGrasp^−/− flies. Enterocytes of NP1>mCD8::RFP fly guts were stained with antibodies against DsRed (green) and nuclei were counterstained with TO-PRO-3 (blue). Lipids were visualized by staining with BODIPY solution (red). For consistency, pseudocolors were used. Confocal microscopic images of whole guts from control (NP1>mCD8::RFP) and dGrasp-mutant flies (NP1>mCD8::RFP;dGrasp^−/−) are shown in (a). Scale bars: 1 mm. Boxed area indicates the posterior midgut where lipids accumulated. Image sections of the boxed area taken from the top (upper, scale bar: 25 μm) and lateral (bottom, scale bar: 10 μm) orientations are shown in (b). c, d Confocal microscopic images of lipid accumulation in the fly guts of the indicated genotypes. The fly genes dGrasp and bmm are homologs of mammalian GRASP and ATGL, respectively. Each gene was expressed in the enterocytes of dGrasp^−/− flies under the control of NP1-GAL4. Lipids were visualized by staining with Nile Red (red) and nuclei were counterstained with TO-PRO-3 (blue). Representative images of the posterior midguts are shown in (c), and quantitative analyses of intestinal lipid accumulation in the indicated genotypes of the flies are presented in (d), n = 4–6. Scale bars: 50 μm. e Quantitative analyses of relative whole-body TG contents in the indicated genotypes of the flies (n = 5). UAS, upstream activation sequence. Data are shown as mean ± SEM. *p < 0.05, **p < 0.01. All p values were calculated by ANOVA followed by Tukey’s multiple comparison tests. Source data are provided as a Source Data file.