Identification of the vitellogenin proteins in the newt Pleurodeles waltl (urodele amphibian).

Vitellogenin derived from the blood of estrogen-treated Pleurodeles waltl was identified by immunochemical and electrophoretic analyses, using an antiserum against plasma vitellogenin isolated by dimethylformamide precipitation. Pleurodeles vitellogenin migrates as four bands on native PAGE, designated alpha-, beta-, gamma- and delta- VTG, with apparent mol. wts of 250,000, 270,000, 280,000 and 520,000 respectively. In the plasma, from estrogen-treated males like from ovariectomized estrogen-treated females, an additional band (mu-VTG) was found by native PAGE, never observed in estrogen-treated female plasma. It has a mol. wt of about 380,000 and shows complete immunological cross-reactivity with the vitellogenin antiserum. At least two polypeptides, termed VTG-I and VTG-II (mol. wt = 180,000 and 210,000) were identified by SDS-PAGE. Rocket immunoelectrophoresis displays three distinct precipitate lines indicating major immunological differences between the plasma vitellogenins.