Fig. 2: Loss of Mettl1 results in absence of mature sperm in the testis.

a Schematic diagram of Drosophila spermatogenesis. The genes indicated below are markers used to identify each stage of spermatogenesis. (GSC; germline stem cell, CySC; cyst stem cell) (b) Immunostaining of Mettl1-Flag in the testis. yw is a wild-type control. (Left) Overall view of testis. (Right) Zoom-in view of the white box in panel. c Transparent image of seminal vesicle (arrowheads) from control (yw) and Mettl1-KO (Mettl1^KO1) males. d Representative images of Boule localization in testes from WT (yw) and Mettl1-KO (Mettl1^KO1) adult males. Testes were stained for Boule (green). Dotted line surrounds the region of spermatid elongation defects. e Differential interference microscopy image of spermatid bundles (arrowheads) in control (yw) and Mettl1^KO1 testes. f Immunostaining of acetylated-Tub in WT (yw) and Mettl1-rescue (Mettl1^KO1; [Mettl1]) testes. Arrowheads show elongated spermatids. g Male fertility assay at 25 °C using WT (yw), WT with Mettl1 transgene driven by Nanos promoter (yw; [nosP-Mettl1]), Mettl1-KO (Mettl1^KO1) and Mettl1-KO with Nanos-driven Mettl1 (Mettl1^KO1; [nosP-Mettl1]). In box plots, central bands, upper and lower edges of box plots represent median, first and third quartiles, respectively. Upper and lower whiskers represent maximum, and minimum values. Two-sided P-values were calculated using Tukey’s HSD test. The number (n = ) below the box plot indicates the sample size. Each immunostaining were reproduced three times with similar results. Source data of Fig. 2g is provided as a Source Data file. Scale bars of b (left), c, d, e, and f = 100 μm, and b (right) = 50 μm.