title: Coupling of histone mRNA levels to radioresistant DNA synthesis in ataxia-telangiectasia cells.
abstract: Cloned genomic DNA for human histone H1, H3 and H4 genes has been used to determine the effects of gamma-radiation on histone mRNA levels and synthesis in ataxia-telangiectasia cells. Synthesis of histone mRNA was determined in cells synchronized with aphidicolin. Effects of irradiation on DNA synthesis and passage through S phase were also monitored. Irradiation was found to slow the passage of control cells through the cell cycle but had no effect on progression of ataxia-telangiectasia cells. H1 and core histone mRNA synthesis was inhibited by radiation in two control cell lines after release from aphidicolin block. No inhibition was observed in one ataxia-telangiectasia cell line and a small degree of inhibition in a second. An increased level of mRNA was observed in both irradiated control and ataxia-telangiectasia cells at 5-7 h post-irradiation compared to unirradiated cells. Similar results were obtained in log phase cells. These results demonstrate that histone mRNA synthesis is radioresistant in ataxia-telangiectasia cells and is coupled to radioresistant DNA synthesis in these cells.
mesh_terms: D001260:Ataxia Telangiectasia / Q000378:metabolism*; D002460:Cell Line; D002469:Cell Separation; D004247:DNA / Q000096:biosynthesis*; D004261:DNA Replication / Q000528:radiation effects*; D005434:Flow Cytometry; D005720:Gamma Rays; D005796:Genes; D006657:Histones / Q000235:genetics*; D006801:Humans; D007399:Interphase; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000528:radiation effects
chemical_list: D006657:Histones; D012333:RNA, Messenger; D004247:DNA