Intestinal Citrate Efflux Is Required for Testis Germline Maturation
(A) CE-MS measurement of hemolymph citrate in control males and in males after R2 and R4 EC-specific KD of plasma membrane Indy citrate transporter. n = 4 samples, each containing hemolymph from 120–280 flies.
(B) Immunohistochemical analysis of testis anatomy and germline maturation based on expression of Fasciclin 3 (Fas3, labeling hub cells (white arrowhead), green), DAPI (blue) and number of phospho Histone3 (pH3)-positive cells (staining mitotic (arrow) and meiotic (asterisk) cells, red) in testes of control males and males with R2 and R4 EC-specific Indy KD.
(C) Quantification of Cookie monster (Comr) expression pattern (ComrGFP, green) in control testes and testes after R2 and R4 EC-specific Indy KD. Representative images shown (DNA: DAPI, blue).
(D–F) Representative images (DNA: DAPI, blue; protein, green) and quantifications of ComrGFP (D), BouleGFP (E), cleaved Dead caspase-1 (Dcp-1) (F) expression in testes of control males and in males after testis-specific Indy KD (traffic jam (tj)-Gal4 line).
(G) Quantification of cleaved Dcp-1 expression (green) in control testes and testes after testis-specific Indy KD (eyes absent (eya)-Gal4 line). Representative images shown (DNA: DAPI, blue).
(H) GC-MS measurements of the testis concentration of citrate and 2-hydroxyglutarate (2HG) in control males and in males after R2 and R4 EC-specific Indy KD. n = 4 samples, each containing 150 dissected testes.
(I) Quantification of FRET signal in late somatic testis cells expressing CIT8 from control males or males with R2 and R4 EC-specific KD of Maltase-A1 (Mal-A1RNAi).
(J) Food intake quantification based on FlyPAD-monitored sips per male fly after testis-specific Indy KD (tj-Gal4 line). n = testes number analyzed per genotype except for in (J), where n = fly number analyzed.
Scale bars, 200 μm in all images. Asterisks highlighting significant comparisons across male datasets are displayed in a blue box. See Table S2 for metabolites/concentrations. See Table S4 for a list of full genotypes. See also Figure S7 and Table S2.