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 preferably synthesized. When infected cells are heat shocked, however, there is also an inhibition of viral protein synthesis, and there is preferential synthesis of heat shock proteins. Based on these observations, the distribution of Mayaro viral RNA in polysomes and the association of p34 (capsid protein) with ribosomal fractions of the cells under such conditions have been analyzed. During infection, the viral RNA is mainly observed in light polysomes (60% of total viral RNA in the cell) and also in heavy polysomes (13%). However, when infected cells are heat-shocked, the viral RNA is strongly mobilized from heavy polysomes to the light polysomes fraction and an enrichment in the unbound fraction can be noticed. The amount of p34 associated with the ribosomal fraction was also shown to be decreased in the heat shocked cells. These data lead to the suggestion that two mechanisms could be involved in the inhibition of Mayaro virus protein synthesis in response to heat shock: (1) mobilization of Mayaro virus RNA from heavy to light polysomes; (2) a decrease in the amount of the p34 within the ribosomal fraction.