Combined effects of ionizing radiation and cycloheximide on gene expression

✍ Scribed by Gayle E. Woloschak; Paolo Felcher; Chin-Mei Chang-Liu

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 560 KB
• Volume: 13
• Category: Article
• ISSN: 0899-1987
• DOI: 10.1002/mc.2940130108

✦ Synopsis

We performed experiments t o determine the effects of ionizing radiation exposure on expression of genes such as p-actin, c-fos, histone H4, c-myc, c-jun, Rb, andp53 after exposure o f Syrian hamster embryo (SHE) cells t o the protein synthesis inhibitor cycloheximide. The purpose of these experiments was t o determine the role of a labile protein in the radiation-induced response. The results revealed that when ionizing radiation (either fission-spectrum neutrons or y rays) was administered 15 min after cycloheximide treatment of SHE cells, the radiation exposure reduced cycloheximide-mediated gene induction o f c-fos, histone H4, and c-jun. In addition, dose-rate differences were found when radiation exposure most significantly inhibited the cycloheximide response. Our results suggest that ionizing radiation does not act as a general protein-synthesis inhibitor and that the presence o f a labile protein is required for the maintenance o f specific gene transcription and mRNA accumulation after radiation exposure, especially at high dose-rates.