title: Gene expression profile of human cells irradiated in G1 and G2 phases of cell cycle.
abstract: The response of cells to ionizing radiation has long been known to result in alterations in gene expression. Here we examined the expression patterns of synchronized HeLa cells in G1 or G2, after exposure to 2Gy of X-rays on microarrays allowing evaluation of over 12,000 human genes. The analysis showed induction of at least twofold for 257 different genes, after irradiation of cells in G1 and down-regulation of 42. The altered transcription patterns involved genes belonging to cell cycle pathways, DNA repair, oncogenes, histones, heat shock genes, mitochondrial and ribosomal proteins, transcription and translational regulators and genes encoding cytoskeleton components. HeLa cells are deficient in p53 and none of the induced genes have previously been identified as regulated by p53. One hundred and seventy-seven genes were up-regulated and 26 genes were down-regulated after irradiation in G2. Surprisingly most of the up-regulated genes in both phases of the cell cycle encode ribosomal proteins. These studies have revealed cell cycle dependence on radiation-induced gene induction and have permitted the identification of previously known as well as unknown genes associated with radiation-induced altered expression.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Vermont, 226 Stafford Hall, Burlington 05401, USA. mchaudhr@zoo.uvm.edu
authors.forename: M Ahmad
authors.initials: MA
authors.lastname: Chaudhry
authors.forename: Lewis A
authors.initials: LA
authors.lastname: Chodosh
authors.forename: W Gillies
authors.initials: WG
authors.lastname: McKenna
authors.forename: Ruth J
authors.initials: RJ
authors.lastname: Muschel
mesh_terms: D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics; D016193:G1 Phase / Q000235:genetics / Q000528:radiation effects*; D016195:G2 Phase / Q000235:genetics / Q000528:radiation effects*; D005720:Gamma Rays; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects*; D016158:Genes, p53; D006367:HeLa Cells / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000528:radiation effects; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency
chemical_list: D018797:Cell Cycle Proteins; D009363:Neoplasm Proteins; D012269:Ribosomal Proteins; D016159:Tumor Suppressor Protein p53