Nipbl localization on oocyte chromosomes. Immunofluorescence images of chromosome spreads during meiotic prophase stages in fetal ovaries stained with antibodies against Nipbl (green) and Sycp3 (red). Images for each stage represent both Nipbl A and B isoforms as no significant difference was identified in Nipbl signal patterns generated by all three antibodies (see the main text). More than 10 nuclei were examined in each stage. DNA was counterstained with DAPI. E, early; L, late. Scale bar 5 μm.