Glycoprotein patterns in different established cell lines of Drosophila melanogaster responding to 20-hydroxyecdysone

Abstract

Newly synthesized glycoproteins labelled with [ 3 H]N- acetyl- d- glucosamine were studied by two-dimensional gel electrophoresis in a primary culture of embryonic cells and in five established cell lines independently obtained from embryonic cells of Drosophila melanogaster. The patterns of major glycoprotein fractions were different in different cell lines, whereas the protein spectra proved to be basically similar. Characteristic glycoprotein patterns were maintained after prolonged cultivation. Four “obligatory” acid glycoprotein fractions were shown to be present in all the tested cell cultures. All the independent lines, except vg and the primary cell culture, proved to contain a family of glycoproteins (or its components) with similar properties. The family contained up to 12 discrete components with similar molecular weights but with different isoelectric points. The various components constituting the family were labelled to different degrees in the different lines. 20-Hydroxyecdysone either increased the net synthesis of the most acid fractions in the family (line D) or induced the synthesis of the majority or all of the 12 fractions making up the family (lines G 2 and pE). The effects of the hormone on glycoprotein net synthesis were insignificant in lines Schneider-2, vg and in a primary culture of embryonic cells. The results demonstrate that the tested cell cultures possess different levels of competence for 20-hydroxyecdysone, which can induce the synthesis of a specific glycoprotein family.