The polypeptides induced in Drosophila cells by Drosophila C virus (strain Ouarzazate)

Abstract

The Ouarzazate strain of Drosophila virus (DCV 0) was grown in Drosophila melanogaster tissue culture cells, and [ 35S]methionine-labeled virions were found to contain a group of major structural proteins with a molecular weight of ≌30,000 as well as several minor proteins of higher molecular weight and a protein of ≌10,000 daltons. Using a range of pulses, chases and gel systems, examination of the intracellular proteins induced by DCV 0 showed the presence of 17 polypeptides not found in uninfected cells. The synthesis of virus-induced polypeptides was extremely asymmetric with a rapid appearance of the major virus structural proteins and a much slower appearance of the lowest molecular weight structural protein (VP4). Processing of virus-induced proteins including the appearance of VP4 was demonstrated using pulse-chase after pulsing with [ 35S]methionine. While the highest molecular weight induced protein found in infected cells was 146,000, pretreatment of cells with iodoacetamide resulted in the appearance of a protein with a molecular weight of ≌200,000. The evidence presented in this paper supports the inclusion of DCV 0 in the Picornaviridae group.