APH-2 protein is first detected during oogenesis. APH-2 is associated with the plasma membranes that partially surround the developing oocyte nuclei and with the surface membranes of mature oocytes. In newly fertilized eggs and in early cleavage stage embryos, APH-2 is associated with the peripheral membranes of all blastomeres. The APH-2 protein can be detected on, or near, plasma membranes throughout the first 5-6 hours of embryogenesis. The APH-2 protein that is observed after the 28-cell stage may represent protein that persists from maternal expression of
aph-2, or may result from de novo embryonic expression.
aph-2 mutant embryos analyzed in this study lack both maternal and embryonic
aph-2(+) activity, and fail to show any detectable APH-2 protein. Embryonically expressed APH-2 protein was not detected in early embryos that were obtained from
aph-2 mutant hermaphrodites mated with
aph-2(+) males.