CLONING OF CDNA FOR VITELLOGENIN OF ATHALIA (HYMENOPTERA) ROSAE AND CHARACTERIZATION OF THE VITELLOGENIN GENE-EXPRESSION

Athalia rosae (Hymenoptera) was previously shown to have two vitellins (L-Vn and S-Vn) and the two corresponding vitellogenins (L-Vg and S-V g). A cDNA expression library was constructed from poly(A)+ RNA prepar ed from adult female fat body cells, and was screened for the vitellog enins by using antisera against the L- and S-Vn, respectively. Examina tions of cloned cDNAs show that the vitellogenin gene is transcribed a s a single unit, with the 5'-terminal site coding for the S-Vg and the 3'-terminal site for the L-Vg. Nucleotide sequence at the 5'-end sugg ests the presence of a 16 amino acid-long signal peptide. Deduced amin o acid sequence following the signal peptide shows a complete match wi th up to the 28 N-terminal amino acid sequence determined on S-Vn. The S-L Vg boundary with deduced amino acid sequence matching with 6 N-te rminal amino acid sequence determined on L-Vn is also detected. Northe rn blot hybridization analysis shows that the vitellogenin gene is exp ressed in the female fat body as a single 6.5 kb mRNA but not in the o vary, and not in the male fat body. Western blot analysis detects a la rge precursor polypeptide, reacting with the anti-L-Vn and S-Vn antise ra, in the adult female fat body.