Figure 2.—

(A) Knock down of the D-DDB1 level by expression of the 650-bp D-DDB1 double-strand RNAs in living flies [UAS-D-DDB1(650)-dsRNA/+; Act5C-GAL4/+] caused melanotic tumors and almost all flies died in the larval stage. A few transgenic flies lived until early pupal stages (B) but none grew to adults. No melanotic tumors or early lethality was observed in control flies carrying a single copy of Act5C-GAL4 (+/+;Act5C/+) (C and D). (A and C) Third instar larvae; (B and D) pupae. (E) Lethality in the transgenic flies expressing D-DDB1(650)-dsRNA. UAS-D-DDB1(650)-dsRNA/UAS-D-DDB1(650)-dsRNA transgenic flies were crossed with Act25-GAL4/Cyo, GFP transgenic flies, and the numbers of F₁ larvae of UAS-D-DDB1(650)-dsRNA/Act25-GAL4 (RNAi active flies without GFP signal) and UAS-D-DDB1(650)-dsRNA/Cyo,GFP (control flies with GFP signal) were counted. The values shown are the rate of the number of UAS-D-DDB1(650)-dsRNA/Act25-GAL4 flies divided by the number of UAS-D-DDB1(650)-dsRNA/Cyo,GFP flies. (F) The flies knocked out D-DDB1 showed melanotic tumors and almost all died at the first instar larval stage. (G and H) The DAPI staining images of the fat body from CgGAL4/UAS-D-DDB1(650)-dsRNA and CgGAL4/+. The bottoms of G and H show high-magnification views of the tops. The shape of nuclei in the CgGAL4/UAS-D-DDB1(650)-dsRNA fly (G) was abnormal as compared with control (H). Arrows indicate the position of the melanotic tumor. Bars, 0.5 mm.