Myc is necessary for starvation-induced autophagy in Drosophila.

<p>(A) <i>Myc</i> depletion in LAMP1-GFP marked fat body cell clones inhibits starvation-induced punctate Lysotracker staining, compared to surrounding control cells that do not express GFP. Mid-L3 stage larvae were analyzed in all fat body experiments unless noted otherwise. (B) Overexpression of Mad also blocks Lysotracker dot formation in cells marked by LAMP1-GFP. (C) Quantification of data presented in panels A and B, n = 7 for all genotypes. (D) Starvation-induced punctate endogenous Atg8a staining is inhibited in <i>Myc</i> RNAi cells marked by LAMP1-GFP expression, compared to neighboring control tissue. (E) Forced expression of Mad also decreases Atg8a dot formation. (F) Quantification of data presented in panels D and E, n = 6 for all genotypes. (G) Starvation leads to the formation of Lysotracker-positive autolysosomes in fat body cells of control L1 stage larvae. (H) A near-complete block of Lysotracker puncta formation is seen in <i>Myc</i> null mutant L1 stage larvae. (I) Quantification of data presented in panels G and H. (J) Double-membrane autophagosomes (ap) and dense autolysosomes (al) degrading sequestered cytoplasmic cargo are observed in midgut cells of control L1 stage larvae. (K) No autophagic structures are seen in midgut cells of L1 stage <i>Myc</i> null mutant larvae. (L) The selective autophagy cargo p62 accumulates in <i>Myc</i> RNAi cells (marked by LAMP1-GFP expression) compared to surrounding control tissue in well-fed animals. (M) Mad overexpression also leads to large-scale accumulation of p62 aggregates. (N) Statistical evaluation of data presented in panels M and N, n = 7 for all genotypes. Scalebars in A, B, D, E, G, H, L, M equal 20 µm. Statistically significant differences are indicated, ** p<0.01.