Main content area

Purification and biochemical characterization of a vitellogenin-like protein from sea urchin

Nishimiya, Osamu, Teraoka, Yoshihiko, Gotoh, Takahiro, Yuhi, Tomoharu, Higuchi, Ichiro, Ura, Kazuhiro, Takagi, Yasuaki
Fisheries science 2019 v.85 no.1 pp. 127-135
Mesocentrotus, Strongylocentrotus, Sudan dyes, affinity chromatography, ammonium sulfate, animal ovaries, anion exchange chromatography, antiserum, eggs, fractionation, gametogenesis, gel chromatography, immunochemistry, polyacrylamide gel electrophoresis, rabbits, staining, tandem mass spectrometry, testes, yolk proteins
The major yolk protein in sea urchins is a transferrin-like protein. In this report, a new component was detected in gonad extracts of Strongylocentrotus intermedius and Mesocentrotus nudus, which cross-reacts with antiserum against egg yolk proteins. We tentatively named them egg yolk-related proteins siYRP and mnYRP. The siYRP was purified from testis of S. intermedius by ammonium sulfate fractionation, anion exchange chromatography, affinity chromatography and gel filtration. Purified siYRP was > 900 kDa in size. The siYRP purified on SDS-PAGE under reducing conditions gave seven bands, corresponding to 93, 213 and > 250 kDa. Purified mnYRP displayed similar structural characteristics as siYRP. Purified siYRP and mnYRP were identified by tandem mass spectrometry and renamed as siVitellogenin (Vtg)-like and mnVtg-like proteins, respectively. Both Vtg-like proteins were confirmed to be lipoglycoproteins by staining with Sudan black and periodic acid-Schiff. A specific antiserum against the siVtg-like protein was raised in rabbit. Antiserum against the siVtg-like protein immunostained siVtg-like and mnVtg-like proteins. Immunochemical methods using the antiserum revealed that siVtg-like and mnVtg-like proteins were present in the ovary, testis and unfertilized eggs of both species. These results indicated that Vtg-like proteins have important physiological functions for gonadal growth and gametogenesis in sea urchins.