Fig. 2. Cytological characterization of primary spermatocyte nuclei of D. melanogaster using Jel318 and Jel466 antibodies. (A,B) Phase contrast images. (A',B') Immunostaining images. (A,A') Jel318 immunostaining of slides pre-treated with trypsin; the antibody specifically recognizes the kl-3 loop but no other intranuclear structure. (B-B') Jel466 immunostaining; the antibody specifically recognizes the kl-5 loop although in some cases also a faint fluorescence on kl-3 loop is present. Note that Jel318 decorates a continuous kl-3 filament whereas Jel466 recognizes a granular matrix inside the kl-5 loop.