The synthesis of vitellogenins by the digestive gland of Helix aspersa: evidence from cell-free translation of mRNA.

All the RNAs were extracted separately from the gonads and digestive glands of the garden snail Helix aspersa. After separation by oligo-dT-cellulose chromatography, the mRNA were evaluated using optical density measurements and agarose gel electrophoretic analysis and then used in a cell-free translation system: a rabbit reticulocyte lysate added with 35S methionine. The in vitro synthesized proteins were characterized by immunoprecipitation with polyclonal antibodies which were raised against mature oocyte proteins. The proteins were then evaluated quantitatively using liquid scintillation counting and qualitatively using SDS polyacrylamide gel electrophoresis and fluorography. The results demonstrated that the digestive gland of the garden snail is a vitellogenin synthesis site.