Fig. 2.

Seryp is taken up by oocytes from plasma, probably through interaction with Vitellogenin. (A) Seryp species have different electrophoretic mobilities. Female X. laevis plasma contains a 54 kDa Seryp species, the precursor of the egg forms p50 and p48. Early oocytes contain a ∼60 kDa protein that cross-reacts strongly with anti-Seryp antibody. Asterisk indicates cross-reaction with highly abundant serum Vitellogenin. Gel loading was approximately normalized by oocyte volume. (B) Reciprocal co-immunoprecipitation of Vitellogenin and Seryp from female X. laevis plasma. Antibody cross-linked beads were prepared from IgG purified from pre-immune and immunized anti-Vtg rabbit serum, as well as from pre-immune and immunized anti-Seryp rabbit serum. Western blots were sequentially probed with anti-Vtg and anti-Seryp antibodies.