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Studies of SV40-infected Werner syndrome fibroblasts
Abstract:
Skin fibroblasts from patients with the Werner syndrome (WS) and fibroblasts from normal donors were infected with SV40 of a wild type strain (777) or of a temperature-sensitive mutant strain (tsA900). The infected WS cells and the infected normal cells proliferated at permissive temperatures, and then entered into "crisis" in which state they ceased proliferation. In their proliferative phase, both WS and normal cells infected with tsA900 proliferated rapidly at 34 degrees C, but their proliferation slowed down at 39 degrees C. Some lines of infected WS cultures accrued more population doublings before they entered into "crisis" than uninfected WS cells. Among 13 series of infected cultures, one line, which had been infected with 777, passed through "crisis" and proliferated indefinitely. This line (PSV811) was from a 29-year-old female WS patient. We compared a cloned line of PSV811 with a permanent line of SV40-infected WI-38 normal human fibroblasts (VA13 2RA). Cells of both lines, PSV811 and VA13, were epithelioid, did not shed viruses into the culture medium, and their chromosome number distributed broadly across the diploid range. An autoradiographic study suggested that both lines are capable of unscheduled DNA synthesis. In both cultures, the rate of proliferation depended on the concentration of fetal bovine serum in culture medium. However, the PSV811 cells grew slower, and produced colonies with fewer cells than did VA13 cells. The frequency of sister chromatid exchange was about 70% higher in PSV811 than in VA13. In an adjunct paper, Murata and others report that the percentage of hyaluronic acid in total acidic glycosaminoglycans released into culture medium was larger in PSV811 than in VA13. We concluded from these results that PSV811 is not a contaminant of VA13, that an SV40 infection partly modify the proliferative characteristics of WS cells, and that SV40-infected WS cells and permanent lines obtained therefrom, are useful in furthering the study of WS.