Identification and preliminary characterization of white sturgeon (Acipenser transmontanus) vitellogenin mRNA.

Vitellogenesis was induced in white sturgeon by administration of estrogen through silastic implants. Vitellogenin mRNA was identified by agarose gel electrophoresis and cell-free translation. A highly abundant 5.7-kb mRNA was induced in the liver of estrogen-treated sturgeon. Cell-free translation of poly(A)+ mRNA showed the induction of two high-molecular-weight proteins of 180 and 120 kDa. These two proteins, encoded by the 5.7-kb mRNA(s), were immunoprecipitated by antiserum to serum from vitellogenic sturgeon. Immunoprecipitations also showed the presence of four other serum proteins synthesized by the liver of estrogen-treated sturgeon. The induction of vitellogenesis by estrogen in sturgeon, which are a primitive teleost, was found to be similar to induction of vitellogenesis in amphibians, avians, and other teleosts. Estrogen treatment induced a highly abundant vitellogenin mRNA as well as several mRNAs for other serum proteins. However, the presence of two distinct vitellogenin monomers in the cell-free translation assay was significantly different from the results in other species.