Identification of a novel nuclear guanosine triphosphate-binding protein differentially expressed in renal disease

A novel guanosine triphosphate-binding protein, chronic renal failure gene (CRFG), was discovered by differential display PCR to be regulated differen tially in renal disease. Within the rat kidney, CRFG mRNA was localized to the outer medulla and was highly expressed in epithelial cells. The specifi c renal expression of CRFG mRNA in the outer medulla was reduced dramatical ly in several rat models of renal disease, including diabetic nephropathy, partial nephrectomy, ischemia, and anti-Thy1.1-induced nephritis. CRFG was localized selectively in the nucleus of human and rodent cells, as determin ed by immunocytochemistry and green fluorescence fusion protein. Cellular m RNA levels of CRFG were also increased after serum administration, when cel ls proliferate. These data suggest that CRFG may be involved in regulating guanosine triphosphate-dependent nuclear events that are associated with ce ll proliferation and that are important in normal renal function and essent ial for growth and development.