Effects of environmental level magnetic field exposures on transcription of CMV immediate early promoter DNA in a cell-free in vitro transcription system

Effects of environmental levels of magnetic fields (MFs) on RNA synthesis h ave been investigated by using a cell-free system for in vitro transcriptio n. Transcription reaction mixtures containing CMV immediate early promoter DNA plus HeLa cell nuclear extracts were exposed to each of three different MF field strengths, i.e., 10, 50, and 100 mu T. Each MF exposed extract wa s paired with a simultaneous sham-exposure control. The present results sho w no significant differences in amounts of RNA synthesis in extracts of MF exposed compared with that in the sham controls. This finding is in contras t to results of prior studies of DNA synthesis in cell-free systems that sh owed MF exposure effects. The results of the present cell-free system studi es suggest that the marked differences of MF exposure effects on DNA and on RNA synthesis direct attention to the complexity involved in confirming si gnificant effects of exposures to environmental levels of MFs in biosystems in vivo and in vitro. (C) 1999 Wiley-Liss, Inc.