FIG. 2.

Hsp90 inhibition reduces FHV protein A mRNA association with polysomes. (A) Drosophila S2 cells stably transfected with pS2FA were induced with Cu²⁺ in the presence of dimethyl sulfoxide (DMSO) or geldanamycin (GA), cell lysates were separated by linear sucrose gradient density centrifugation, equal-volume fractions were recovered from the top (low density) to the bottom (high density) of the gradient, total RNA was recovered by phenol-chloroform extraction and ethanol precipitation, and FHV protein A (PtnA) mRNA content was analyzed by Northern blotting with a ³²P-labeled riboprobe (25). (B) Quantitative data for the effect of geldanamycin on protein A mRNA polysome association. The total protein A mRNA recovered was the sum of the densitometry analysis of lanes 1 to 8 (see above [A]). (C) Ethidium bromide-stained rRNA in sucrose gradient fractions from cells treated with dimethyl sulfoxide, geldanamycin, or the general translation initiation inhibitor hippuristanol (HIP). The quantitative values represent the percentages of total rRNA present in fractions 3 and 4 or fractions 7 and 8. Results are representative of two independent experiments, and for B and quantitative values in C, results represent the means from those experiments.