Serum concentration and increased temperature alter Mayaro virus RNA and protein synthesis in Aedes albopictus (mosquito)-infected cells

We have previously shown the inhibition of Mayaro virus multiplication in Aedes albopictus-infected cells maintained at a supraoptimal temperature for growth (37§C) and a stimulation of virus production in response to high serum concentrations in the incubation medium. In the present study, we addressed the question of how the effect of continuous heat stress and high serum concentration soon after infection interfere with virus macromolecule synthesis. Cells maintained at 28§C in the presence of 2 percent serum synthesized a viral genomic RNA of 12 kb and a subgenomic RNA of 5.2 kb 6 h post-infection. Analysis of the protein profile showed the presence of the viral nucleocapsid protein of 34 kDa (P34). However, if infected cells were maintained at 37§C, a smear starting immediately below the 5.2-kb RNA was noticed and the viral P34 was not detected by SDS-PAGE. Addition of 10 percent serum to the growth medium of infected cells maintained at 37§C results in a viral RNA profile and proteins synthesis similar to those observed in cultures kept at 28§C, i.e., the smear was not observed and the P34 protein was detected. The results suggest that the inhibition of virus multiplication by temperature may be related to the inhibition of viral nonstructural protein synthesis early during infection. The presence of high serum levels in the incubation medium protects macromolecule synthesis against heat stress

Translocation of heat shock proteins into isolated nuclei of Aedes albopictus cells

Labelled heat shock proteins of 82 kDa,70 and a group of low molecular weight are present in the post-mitochondrial supernatant obtained from Aedes albopictus cells.These proteins in the post-mitochondrial extract are transported specifically to the nuclear compartment when incubated with isolated unlabelled nuclei.The relative amounts of each protein transported were 4.7,24.1 and 3,1% for the 82-k-Daand 70-kDa and for the low molecular weght proteins, respectively.Incubation of radiolabelled post-mitochondrial extract with unlabelled nuclei at 30 C or 37 C did not modify the perecentage of proteins translocated

Effect of high temperature on Aedes albopictus cells infected with Mayaro virus

the multiplication of Mayaro virus in Aedes albopictus cells was drastically inhibited after incubation at 37-C. The effect of short-term exposure of infected cells to high temperatures (heat shock) produced a preferential translation of the heat shock messengers when compared to the viral mRNAs. When cells were shifted back to 28-C (the optimum growth temperature for Aedes albopictus cells), preferential translation of viral mRNA occurred. Although the infected cells were programmed for preferential translation of viral messengers, the therminal treatment was able to shif the translational machinery towards synthesis of heat shock proteins