CPEB is a nuclear-cytoplasmic shuttling protein. (A) Left: Western blot of Xenopus oocyte lysate demonstrated the specificity of CPEB antibody used in this study. Right: Nuclei and cytoplasms from oocytes of different stages were manually separated and probed on Western blots for CPEB and tubulin. (B) Stage VI oocytes were treated with 200 nM leptomycin B overnight; nuclei and cytoplasms were then manually separated and probed for CPEB, tubulin as a cytoplasmic marker, and histone H4 as a nuclear marker. (C) MEFs were transfected with CPEB-HA, some of which were then treated with 10 nM LMB for 5 h. The HA epitope was located by indirect immunofluorescence. (D) Lampbrush chromosomes were prepared and immunostained for symplekin and CPEB. Some preparations were treated with RNase before immunolocalization for CPEB. The chromosomes were also stained with DAPI.
