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-rate and cycloheximide on expression of cytoskeletal and matrix elements in Syrian hamster embryo cells. Results here demonstrated little effect of dose-rate for fission-spectrum neutrons when comparing expression of α-tubulin or fibronectin genes. Effects of cycloheximide, however, revealed several findings: (a) Cycloheximide repressed accumulation of α-tubulin following exposure to high dose-rate neutrons or γ-rays. (b) Cycloheximide did not affect accumulation of mRNA for actin genes, (c) Cycloheximide abrogated the moderate induction of fibronectin-mRNA which occurred following exposure to γ-rays and high dose-rate neutrons. These results suggest a role for labile proteins in the maintenance of α-tubulin and fibronectin mRNA accumulation following exposure to ionizing radiation.