Fig. 8: Amino acid availability controlled Notch protein abundance and crystal cell differentiation.
Anti-Notch immunofluorescence (A) indicated that Notch protein levels were higher in lymph glands of larvae grown in culture medium containing high yeast (4% w/v) in comparison to larvae grown in normal medium (2% yeast w/v). B Notch immunofluorescence intensity (arb. units) relative to the one of larvae reared in normal food. Unpaired two-tailed Student’s t-test (****, p < 0.0001). Normal food, n = 13 primary lobes; high yeast, n = 14. Crystal cell differentiation increased in larvae grown in the yeast-rich medium, in comparison to normal fly food (C), as assessed by anti-Lozenge (Lz) immunofluorescence in Z-stack projections of lymph gland lobes (dashed line). The increase of crystal cell differentiation observed in (C) was suppressed after overexpression of Atg1 (D) with domeMESO-Gal4 driver. RNAi-mediated knock-down of the amino acid transporter Slimfast (Slif) prevented the increase of crystal cell differentiation provoked by the addition of extra-yeast in the fly food (E). Overexpression of Slif led to increased crystal cell differentiation in larvae reared in normal food, compared with wild type animals (C, F). G Quantification of the results of panels (C–F). One-way ANOVA followed by Tukey’s test for multiple comparisons. Different letters represent statistically significant differences (p < 0.05). For the wild type genotype, n = 144 primary lobes in normal food and n = 51 in high yeast; for UAS-Atg1, n = 24 in normal food and n = 24 in high yeast; for slifRNAi, n = 75 in normal food and n = 44 in high yeast; for UAS-slif, n = 77. B, G Box plots show the data distribution, with the box representing the interquartile range, the central line indicating the median, and whiskers extending to the minimum and maximum values. Source data for plots are provided as a Source Data file.
