EXPRESSION AND ACTIVITY OF P67 ARE INDUCED DURING HEAT-SHOCK

p67, a cellular glycoprotein, protects eIF2 alpha from phosphorylation by inhibitory kinases such as PKR and HCR. p67 promoter contains heat shock element (HSE), To investigate whether this HSE of p67 has any r ole during heat-shock, rat tumor hepatoma cells were transiently trans fected with CAT reporters linked to p67 promoter with HSE and without HSE, Heat shock induced CAT activity when p67 promoter contained HSE a nd this induction was not observed when HSE was deleted from the p67 p romoter. In response to heat-shock, the endogenous p67 mRNA was also i nduced to more than 36-fold, and much of it translated into protein wh ich was modified by GlcNAc moieties. The time of induced glycosyl modi fication at the later stages of the heat-shock correlates with the red uced level of eIF2 alpha phosphorylation, During later stages of the h eat shock of animal cells, there is a preferential translation of a sm all class of messages encoding heat shock proteins. Our results sugges t that the expression and activity of p67 are induced at the later sta ges of the heat-shock, and may be involved in the preferential transla tion of the heat-shock messages. (C) 1998 Academic Press.