BLOOMS SYNDROME CELLS GM1492 LACK DETECTABLE P53 PROTEIN BUT EXHIBIT NORMAL G1 CELL-CYCLE ARREST AFTER UV IRRADIATION

The tumor suppressor gene p53 is thought to be a key factor in the ons et of G1 cell-cycle arrest following DNA damage. However, here we desc ribe cells derived from a patient with Bloom's syndrome, lacking any d etectable p53 protein, that still shows a functional G1 cell-cycle che ckpoint after irradiation with UV-C. Comparison with cells from other Bloom's patients showed that the absence of p53 protein is not a speci fic characteristic of Bloom's syndrome.