Endogenous RME-2 yolk receptors are found sparsely distributed on the oocyte plasma membrane and are enriched in cortical vesicles and tubules representing early and recycling endosomes. Little or no yolk receptor can be detected in the late endosomal yolk granules in wild-type oocytes. In
rme-4 mutant oocytes, the intensity of cortical RME-2 detected by immunofluorescence was reduced by about twofold. Conversely, the diffuse RME-2 signal deeper in the cytoplasm was increased in
rme-4 mutants.