Proteasomes (prosomes) inhibit the translation of Tobacco mosaic virus RNA by preventing the formation of initiation complexes

Abstract

Proteasomes (prosomes) are large multiprotein complexes. They are involved in protein degradation of ubiquitin-conjugated proteins and in the generation of MHC class I peptides. We gave further evidence that they interfere with in vitro protein synthesis. Proteasomes inhibit the translation of Tobacco mosaic virus RNA. Analysis of cell-free systems by sucrose gradient centrifugation revealed that they prevent the formation of 80S initiation complexes but not the early phase of initiation.

Identification and Initial Characterization of a Specific Proteasome (Prosome) Associated RNase Activity

“…While no inhibition was observed with globin mRNA and cellular mRNAs of HeLa cells, the translation of TMV-RNA and mRNA isolated from adenovirusinfected HeLa cells was impeded (Horsch et al, 1989). Recent work of our laboratory indicates that proteasome prevents the formation of 80 S initiation complexes but not the early phase of initiation (Homma et al 1994). In addition, we have shown that proteasomes associated with tobacco mosaic virus RNA and poly(A) + mRNA from adenovirus-infected cells (Horsch et al, 1990).…”

“…Interestingly, the in vitro synthesis of mRNA from adenovirus-infected HeLa cells and the translation of polycistronic TMV-RNA was impeded in the presence of proteasomes, while translation of HeLa mRNA and globin mRNA was not affected under the same conditions (Horsch et al, 1989;Homma et al, 1994). In addition very recent work of our laboratory has shown that translation of TMV-RNA was very sensitive to catalytic amounts of proteasomes.…”

“…As a source of mRNA, we used tobacco mosaic virus RNA which was tested recently with proteasomes in cell free translation systems (Homma et al, 1994). TMV-RNA is a polycistronic messenger with an apparent molecular mass of about 2000 kDa.…”

“…In addition very recent work of our laboratory has shown that translation of TMV-RNA was very sensitive to catalytic amounts of proteasomes. Proteasomes interfere with initiation of protein synthesis, and block the formation of 80 S initiation complexes (Homma et al, 1994). However, this cannot be explained simply by the proteolytic activity of proteasomes since mRNAs from HeLa cells were readily translated and the in vitro synthesized proteins were not degraded by proteasomes (Homma et al, 1994;Horsch et al, 1989).…”

HC-Pro Protein of Potato Virus Y Can Interact with Three Arabidopsis 20S Proteasome Subunits In Planta

“…In addition, the proteasome can interfere with the translation of viral RNA and mRNA in virus-infected cells (3,5,8,14,16,22). Ballut et al.…”