Identification of chorion protein precursors and the mRNAs that encode them in Drosophila melanogaster

Specific antisera were generated for major size classes of Drosophila chorion proteins. These antisera were used in conjunction with cell-free translation of follicular RNA to identify precursors, containing signal peptides, for chorion components A1, A2, B1, and B2. An additional precursor cross-reacts with anti-B antisera, although its product appears to correspond to a protein distinct from authenic B proteins. The size classes of mRNA encoding A and B protein precursors have been identified by cell-free translations.