EXPRESSION OF POLYUBIQUITIN AND HEAT-SHOCK PROTEIN-70 GENES INCREASESIN THE LATER STAGES OF DISEASE PROGRESSION IN SCRAPIE-INFECTED MOUSE-BRAIN

We have shown by northern analyses that the expression of the mouse po lyubiquitin C gene is increased severalfold in the brains of mice infe cted with both the ME7 and 87V strains of scrapie. Expression of the p olyubiquitin gene does not change significantly, compared with control s, until the later stages of disease progression when there is a 2.5-f old increase in ME7-infected brains and a 1.8-fold increase in 87V-inf ected brains. The patterns of changes of expression of the polyubiquit in genes in brains infected with the two strains of scrapie resemble t hose of accumulation of ubiquitin-conjugate-positive structures in the brain that are detected immunohistochemically. A similar increase in the expression of a heat-shock protein 70 gene also occurs.