Figure 7.

Idh3b is required for mitochondrial fragmentation and increase in acidic compartments after pupariation in salivary gland cells. Panels show salivary gland cells of the genotypes mito-EYFP Idh3b⁺/Df(3R)Exel6188 (A–D), mito-EYFP Idh3b¹/Df(3R)Exel6188 (E–H), mito-EYFP Idh3b²/Df(3R)Exel6188 (I–L), and mito-EYFP Idh3b³/Df(3R)Exel6188 (M–P). In mid third-instar larvae, mitochondria are unfragmented (A, E, I, and M) and LysoTracker staining is very weak (B, F, J, and N) in all genotypes shown. However, in 8–12 hr APF prepupal glands (C, D, G, H, K, L, O, and P), mitochondria have undergone extensive fragmentation in mito-EYFP Idh3b⁺/Df(3R)Exel6188 animals (C), and LysoTracker staining has increased dramatically (D), consistent with the initiation of autophagic cell death. In glands from mito-EYFP Idh3b¹/Df(3R)Exel6188 and mito-EYFP Idh3b³/Df(3R)Exel6188 prepupae, mitochondrial fragmentation is not as extensive (G and O), and LysoTracker staining increases to a lesser extent (H and P). In glands from mito-EYFP Idh3b²/Df(3R)Exel6188 prepupae, mitochondria do not fragment, but appear clumped (K), and LysoTracker staining fails to increase (L). All panels are at the same magnification (see scale bars in A and B).