Vitellogenin mRNA from Dacus oleae: Characterization, cDNA cloning, and dependence on sex and developmental stage

Abstract

AbstractPoly(A)+ RNA was isolated from 5‐day‐old females of the olive fruitfly Dacus oleae. In vitro translation of mRNA, followed by immunoprecipitation with anti‐vitellin antiserum, demonstrated the synthesis of two vitellogenin polypeptides of 54,000 and 56,000 daltons. In sucrose gradient centrifugation, the vitellogenin mRNA sediments in the 14.4S region that corresponds to an RNA size of approximately 1,600 nucleotides. Translation of poly(A)+ RNA isolated from male flies revealed the presence of small quantities of vitellogenin mRNA, consistent with the finding of vitellogenin in male hemolymph of Dacus. Using the female poly(A)+ RNA population as template, we constructed a cDNA expression library in a lambda gt11 vector, which was screened with anti‐vitellin antiserum. Four recombinant clones were isolated containing inserts of 550–800 bp*, which were identified as vitellogenin cDNA clones by hybrid‐selected translation. All four cDNA clones showed crossreaction with vitellogenin genes of Drosophila melanogaster. The Dacus clones were used as probes to study vitellogenin expression during postembryonic development of Dacus. In females, vitellogenin mRNA appeared at the time of eclosion with increasing accumulation up to the 5th day of adult life; then it reached a plateau. On day 10, the mRNA titer had already started to decrease and on day 25, no vitellogenin mRNA was detectable. In males, vitellogenin mRNA was found up to the 8th day after eclosion, in very low concentrations. No vitellogenin mRNA was present during larval and pupal stages.