Fig. 8

BMP signaling is absent from vasa2-positive germ and stem cells. A,B Schematic of the mesentery morphology at the level of the gonad region in female (A) and male (B) on a transverse section. Gonad highlighted in pink, septal filament highlighted in shades of yellow. C–F Immunostaining of pSMAD1/5 (cyan) and vasa (yellow) in different parts of the gonad region. DNA counterstaining is shown in magenta. C vasa2-positive basiepithelial cells in the reticular tract are pSMAD1/5-negative. D In the gonad region, vasa2-positive basiepithelial cells are pSMAD1/5-negative (white arrowhead). Rarely, pSMAD1/5-positive, vasa2-negative basiepithelial cells are present (blue arrowhead). E vasa2-positive putative germ cells and maturing oocytes are pSMAD1/5-negative. F vasa2 accumulation in the spermatogonia. F’–F”’ Sporadic pSMAD1/5-positive cells in the male gonad do not overlap with vasa2 in the spermatogonia. All stainings were performed at least two times independently with 3 or more animals imaged.mg—mesoglea, oo—oocyte, sp—spermaries, cgt—cnidoglandular tract, rt—reticular tract, rmr—retractor muscle region, gd—gastrodermis, gv—germinal vesicle, spg—spermatogonia