Fig. 4

Depletion of circbabo(5,6,7,8S) promotes the SREBP signaling pathway. A A volcano plot of gene expression profile of cg-gal4 > shcircbabo(5,6,7,8S)-A samples compared to control cg-gal4 > shGFP samples (fat body). Significantly upregulated genes (blue, p ≤ 0.05 and log2FC > 1), downregulated genes (yellow, p ≤ 0.05 and log2FC <  − 1), and genes with no change in expression (green) are shown. B Significantly upregulated genes were grouped into 10 categories based on Gene Ontology analysis. C Total RNA from the fat bodies of indicated genotypes were extracted and RT-qPCR was performed to quantify levels of select RNAs (Student’s t test, n = 3, * p < 0.05; ** p < 0.01; *** p < 0.001; ns, non-significant). D Immunoblot shows levels of the nuclear form of SREBP (nSREBP) are elevated in the fat bodies of cg > shcircbabo(5,6,7,8S) flies. Tubulin serves as a loading control. E Quantification of results in D (n = 3). F–I Nile red was employed to stain LDs in the fat bodies of indicated genotypes. LDs accumulated in the fly fat bodies upon circbabo(5,6,7,8S) depletion (F and G). Knockdown of SREBP in the shcircbabo(5,6,7,8S) background reduces the degree of LD accumulation (compare G and I). Scale bar, 50 μm. J Quantification of LD size in F, G, H, and I (one-way ANOVA with Turkey post hoc test, n = 3, *** p < 0.001). K TG levels in fat bodies of genotypes similar to those in F, G, H, and I were measured and normalized (one-way ANOVA with Turkey post hoc test, n = 3, ** p < 0.01; *** p < 0.001)