DISTRIBUTION OF MAYARO VIRUS-RNA IN POLYSOMES DURING HEAT-SHOCK

Mayaro virus (Alphavirus) infection of Aedes albopictus cells results in inhibition of cell protein synthesis and viral proteins are prefera bly synthesized. When infected cells are heat shocked, however, there is also an inhibition of viral protein synthesis, and there is prefere ntial synthesis of heat shock proteins. Based on these observations, t he distribution of Mayaro viral RNA in polysomes and the association o f p34(capsid protein) with ribosomal fractions of the cells under such conditions have been analyzed. During infection, the viral RNA is mai nly observed in light polysomes (60% of total viral RNA in the cell) a nd also in heavy polysomes (13%). However, when infected cells are hea t-shocked, the viral RNA is strongly mobilized from heavy polysomes to the light polysomes fraction and an enrichment in the unbound fractio n can be noticed. The amount of p34 associated with the ribosomal frac tion was also shown to be decreased in the heat shocked cells. These d ata lead to the suggestion that two mechanisms could be involved in th e inhibition of Mayaro virus protein synthesis in response to heat sho ck: (1) mobilization of Mayaro virus RNA from heavy to light polysomes ; (2) a decrease in the amount of the p34 within the ribosomal fractio n. (C) 1997 Elsevier Science B.V.