Fig. 6. Vasa2 immunostaining of PGCs confirms the absence of germline cells in nanos2^−/− mutants.

(A to H) Transversal sections of the gonadal region and trilobed septal filament of WT male (A and B), WT female (C and D), Nanos2 KO (E and F), and Nanos2::mOr animals [(G and H) mOr fluorophore is depicted in magenta] stained with DAPI (white) and Vasa2 antibody (yellow). Vasa2⁺ cells have been indicated by white arrows. Note that no Vasa2⁺ cells nor mature oocytes or spermatocytes could be detected in Nanos2 mutants, explaining the sterility of the animals after 12 months. If not otherwise indicated, scale bars correspond to 10 μm. (I) Schematic of a gametogenic female mesentery with a trilobed septal filament. Vas⁺, Vasa2-positive putative primordial germ cells; ret. t., reticulate tract; cil. t., ciliated tract; int. t., intermediate tract; cni.-gla. t., cnido-glandular tract.