title: Regulation of FOS by different compartmental stresses induced by low levels of ionizing radiation.
abstract: We irradiated different cellular compartments and measured changes in expression of the FOS gene at the mRNA and protein levels. [(3)H]Thymidine and tritiated water were used to irradiate the nucleus and the whole cell, respectively. (125)I-Concanavalin A binding was used to irradiate the cell membrane differentially. Changes in FOS mRNA and protein levels were measured using semi-quantitative RT-PCR and SDS-PAGE Western blotting, respectively. Irradiation of the nucleus or the whole cell at a dose rate of 0.075 Gy/h caused no change in the level of FOS mRNA expression, but modestly (1.5-fold) induced FOS protein after 0.5 h. Irradiation of the nucleus at a dose rate of 0.43 Gy/h induced FOS mRNA by 1.5-fold after 0.5 h, but there was no significant effect after whole-cell irradiation. FOS protein was transiently induced 2.5-fold above control levels 0.5 h after a 0. 43-Gy/h exposure of the nucleus or the whole cell. Irradiation of the cell membrane at a dose rate of 1.8 Gy/h for up to 2 h caused no change in the levels of expression of FOS mRNA or protein, but a dose rate of 6.8 Gy/h transiently increased the level of FOS mRNA 3-fold after 0.5 h. These data demonstrate the complexity of the cellular response to radiation-induced damage at low doses. The lack of quantitative agreement between the transcript and protein levels for FOS suggests a role for post-transcriptional regulation.
authors.affiliation: School of Biomedical Sciences, University of Ulster, Jordanstown, Co. Antrim BT37 0QB, Northern Ireland, United Kingdom.
authors.forename: O
authors.initials: O
authors.lastname: Al-Assar
authors.forename: T
authors.initials: T
authors.lastname: Robson
authors.forename: S R
authors.initials: SR
authors.lastname: McKeown
authors.forename: I
authors.initials: I
authors.lastname: Gardin
authors.forename: G D
authors.initials: GD
authors.lastname: Wilson
authors.forename: D G
authors.initials: DG
authors.lastname: Hirst
mesh_terms: D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects; D002467:Cell Nucleus / Q000235:genetics / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006801:Humans; D016761:Oncogene Proteins v-fos / Q000096:biosynthesis / Q000235:genetics* / Q000528:radiation effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000528:radiation effects; D015398:Signal Transduction / Q000528:radiation effects; D014316:Tritium; D014407:Tumor Cells, Cultured
chemical_list: D016761:Oncogene Proteins v-fos; D012333:RNA, Messenger; D014316:Tritium