ESTRADIOL-INDUCED SYNTHESIS OF VITELLOGENIN .3. ISOLATION AND CHARACTERIZATION OF VITELLOGENIN MESSENGER-RNA FROM AVIAN LIVER

Abstract The messenger RNA of the hormone-induced protein vitellogenin was isolated from the liver of estrogen-treated roosters. Starting from total polysomal RNA, the vitellogenin messenger was purified 67-fold by oligo(dT)-cellulose chromatography and sizing on a sucrose gradient. The messenger was translated in vitro into a 170000 dalton polypeptide chain, having the immunochemical characteristics of vitellogenin. From electrophoretic and immunochemical analysis of the in vitro product of translation at least 63% of the messenger activity of the RNA preparation could be attributed to vitellogenin mRNA. Gel electrophoresis of the most purified fraction revealed residual contamination with the larger ribosomal RNA species. The molecular weight of the messenger RNA molecule, obtained by contour length measurements in the electron microscope, lies between 2.5 · 10 6 and 2.8 · 10 6 .