[Cellular DNA repair, proliferative activity and biochemical characteristics in the human premature aging syndrome...

Fibroblasts of a patient with the Hutchinson-Gilford progeria show a decreased proliferative activity in culture and run through no more than 19 subcultivations. Progeria cells rejoin gamma-induced single strand DNA breaks to the same extent and with the same rate as do normal cells. Spontaneous and induced by X-ray chromosome aberration frequency in progeria cells does not differ from that in normal cells. The activity of DNA-polymerases alpha, beta and gamma in different way depends on culture conditions in progeria and normal cells, but no expressed deficiency of these enzymes was found in progeria cells. The activity of easy-soluble arginine-specific proteases in progeria fibroblasts is sharply decreased, and sensitivity of proteins in these cells to trypsin-catalyzed hydrolysis is significantly increased compared to that of normal cells. Defect in the turnover of intracellular proteins is considered to be a reason of a rapid accumulation of altered proteins in cycling cells and a possible reason of accelerated ageing of progeria cells in vitro.