title: DNA synthesis in Bloom's syndrome fibroblasts.
abstract: The relationship between relative rates of DNA synthesis and DNA content in Bloom's syndrome fibroblasts (BS cells) was investigated by flow cytometry. The cells were pulse labelled with 5-bromo-2'-deoxyuridine (BrdU). The BrdU content and cellular DNA content of individual BS cells were simultaneously measured by flow cytometry in which the cells were double-stained by a FITC-conjugated anti BrdU monoclonal antibody (mAb) for the BrdU content (green) and by PI (propidium iodide) (red) for total DNA content. Their red fluorescence histograms were analysed by a microcomputer to evaluate the cell fractions of each S compartment. The BrdU uptake in the early S phase of BS cells was lower than that of normal cells (fibroblasts from skin of a normal human), whereas the uptake in the middle and late S phase was essentially the same as that of normal cells. The early S phase in BS cells accounted for over 50% of the S phase cells. These findings suggest that, in comparison with normal cells, the rate of DNA synthesis in the early S phase of BS cells is lower, but is identical to controls in the middle and late S phases.
mesh_terms: D001816:Bloom Syndrome / Q000378:metabolism* / Q000473:pathology; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D002478:Cells, Cultured; D004247:DNA / Q000032:analysis / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007399:Interphase; D007700:Kinetics; D008938:Mitosis
chemical_list: D004247:DNA; D001973:Bromodeoxyuridine