Modulation of tubulin mRNA levels by interferon in human lymphoblastoid cells.

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Abstract
Blot hybridization with labeled tubulin cDNA showed that treatment of Ramos cells, a human cell line of lymphoblastoid origin, with either alpha or beta interferon (IFN) induced a marked increase in the amount of tubulin mRNA sequences. The level of tubulin mRNA sequences increased rapidly after exposure of cells to IFN‐alpha and reached a maximum after 1 h of treatment, which was four times the control level. Treatment with IFN‐beta induced a maximal increase after 4 h; the amount of tubulin mRNA sequences was seven times higher than the control level. The mRNA extracted from IFN‐treated and nontreated cells was translated in vitro in a reticulocyte lysate cell‐free system containing [35S]methionine. Electrophoretic analysis of the labeled cell‐free products showed an increase in the amount of translatable tubulin mRNA that parallels the time course of induction of tubulin mRNA sequences. Two‐dimensional gel electrophoresis of the labeled protein products directed by mRNA indicates that IFN caused a more pronounced increase in the level of alpha‐tubulin than beta‐tubulin mRNA. Treatment with colchicine, which disrupts the cell microtubules, caused a marked decrease in the tubulin mRNA content. Concomitant treatment of the cells with colchicine and IFN abolished the interferon‐dependent induction of tubulin mRNA.