HUTCHINSON-GILFORD PROGERIA FIBROBLASTS EXHIBIT METABOLICALLY NORMAL URIDINE UPTAKE AND RNA SYNTHETIC RATES

The accelerated aging disease Hutchinson-Gilford progeria syndrome dis plays altered messenger RNA levels in cultured fibroblasts, yet little is known of effects on transcription by RNA polymerases other than RN A polymerase II. Total RNA metabolism was examined by incubation of Hu tchinson-Gilford progeria fibroblasts with [5-H-3]uridine in asynchron ous culture. Uptake of radiolabel was quantitative and was incorporate d preferentially (99+/-0.3%) into newly synthesized RNA. Progeria and control cultures showed comparable rates of uptake of radiolabel, time courses of RNA synthesis, and relative intensity profiles of newly sy nthesized ribosomal RNA. These characteristics held over a greater tha n ten-fold range of cell densities (5x10(3) to 8x10(4) cells/cm(2)). P rogeria and control fibroblasts thus have comparable metabolic capacit ies for uridine uptake and net RNA production, emphasizing the relativ e specificity of transcriptional changes previously identified in prog eria cells. (C) 1995 Academic Press, Inc.