title: Dominance of the senescent phenotype in heterokaryons between replicative and post-replicative human fibroblast-like cells.
abstract: In heterokaryons between senescent and young diploid fibroblast-like cells, dominance of the former with respect to nuclear DNA synthesis (incorporation of [(3)H]thymidine) was demonstrated. For identification of the respective partners, double-layer autoradiography was used after the old cells were labeled with [(3)H]methionine and the young cells were labeled with [(14)C]thymidine. Synchrony of nuclear labeling (i.e., all nuclei in a cell labeled with [(3)H]thymidine) was observed in the majority of di- and polykaryons during the second and third of three 24-hr periods of labeling with [(3)H]thymidine. The results are compatible with either terminal differentiation or error theories of clonal senescence.
mesh_terms: D000293:Adolescent; D001345:Autoradiography; D002250:Carbon Radioisotopes; D002459:Cell Fusion; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D002999:Clone Cells / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000378:metabolism; D010222:Parainfluenza Virus 1, Human; D010641:Phenotype; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D014316:Tritium; D004247:DNA; D008715:Methionine; D013936:Thymidine