2-DIMENSIONAL ELECTROPHORETIC MAPPING OF HEPATIC AND RENAL STRESS PROTEINS

Cellular stress proteins and molecular chaperones are responsive to a variety of stressors and therefore comprise an ideal set of proteins w ith the potential to be used as biomarkers of chemical toxicity. We ha ve investigated the expression of a group of well established heat sho ck and glucose-regulated proteins in the rat liver and kidney using la rge-scale two-dimensional protein electrophoresis and computerized ima ge analysis. Our goal was to determine the level of their expression i n unstressed target tissues and map their coordinate positions on conv entional format two-dimensional electrophoresis (2-DE) gels. All the p roteins studied, except for Hsp25 (heat-shock protein) whose expressio n fell below the level of analyzable detection, were constitutively ex pressed in liver and kidney. With the exception of Hsp70, all the stre ss proteins analyzed were constitutively more abundant in the liver th an the kidney. Comparison of the sum total of all stress protein abund ances revealed a nearly threefold higher level of expression in the li ver than the kidney. Our results suggest that this group of proteins h as significant responsibilities in normal, unstressed cells, due to th eir constitutive abundance. Correspondingly, the 2-DE stress protein p attern established in this study may be very useful in toxicologic scr eening as well as describing a broad range of molecular effects of xen obiotic exposure.