EXPRESSION OF CYTOSKELETAL AND MATRIX GENES FOLLOWING EXPOSURE TO IONIZING-RADIATION - DOSE-RATE EFFECTS AND PROTEIN-SYNTHESIS REQUIREMENTS

Experiments were designed to examine the effects of radiation dose-rat e and cycloheximide on expression of cytoskeletal and matrix elements in Syrian hamster embryo cells. Results here demonstrated little effec t of dose-rate for fission-spectrum neutrons when comparing expression of alpha-tubulin or fibronectin genes. Effects of cycloheximide, howe ver, revealed several findings: (a) Cycloheximide repressed accumulati on of alpha-tubulin following exposure to high dose-rate neutrons or g amma-rays. (b) Cycloheximide did not affect accumulation of mRNA for a ctin genes. (c) Cycloheximide abrogated the moderate induction of fibr onectin-mRNA which occurred following exposure to gamma-rays and high dose-rate neutrons. These results suggest a role for labile proteins i n the maintenance of alpha-tubulin and fibronectin mRNA accumulation f ollowing exposure to ionizing radiation.