Stage- and tissue-specific expression of the genes encoding calliphorin, the major larval serum protein of Calliphora vicina.

The stage- and tissue-specific biosynthesis of calliphorin was analysed during the development of the blowfly, Calliphora vicina. Western blot analyses show that the protein is not present in eggs, whereas it can be detected in fat body, brain, imaginai disk, salivary gland and epidermis throughout all postembryonic stages, including the adult one. By Northern analysis a unique 2.6 kb mol.wt. mRNA coding for calliphorin is identified exclusively in the fat body tissue of larvae, pupae and adults. Hybridization experiments of in vivo labelled poly(A)+ RNA with filter-bound calliphorin genes indicate that the genes are transcribed until pupariation. However, the translation of the calliphorin mRNA stops at the end of the feeding stage, as shown by [35S]-methionine incorporation.