Mise en évidence de deux étapes arginino-dépendantes du cycle de multiplication du virus vaccinal: Rôle des polyamines dans la synthèse des ARNm tardifs

Abstract

The multiplication of vaccinia virus in KB cells is dependent on arginine. In the absence of arginine, the synthesis of late mRNA does not occur. In order to characterize the mechanism by which the synthesis of late mRNA is dependent on arginine, it has been demonstrated that ornithine and the polyamines derived from it — putrescine, spermidine and spermine — can replace arginine and allow the synthesis of late mRNA. In contrast, arginine cannot be substituted for ornithine or the polyamines to allow the production of infectious particles. Thus, these are two arginine-dependent steps in the multiplication cycle of vaccinia virus: the synthesis of late mRNA in which polyamines are involved and a later step, viral maturation, which is presumably dependent on the synthesis of one or several arginine-rich proteins. The existence of two arginine-dependent steps has also been demonstrated by electron microscopic studies. The first step, which is the formation of immature nucleoid containing particles, requires the presence of polyamines. The second step is the formation of mature virions.