ABSTRACT
The level of c-myc transcripts is increased in cells exposed to extremely low frequency (elf) electromagnetic (EM) fields at 60 Hz. The aim of the present experiments was to determine if regulatory regions upstream of the c-myc gene modulate the response to EM fields. DNA upstream of P1 of both mouse and human c-myc genes was transfected into cells as CAT constructs. The presence of DNA 5' to the human or mouse myc genes results in increased expression of CAT following 20 min exposures of cells to 60 Hz elf EM fields. Specific portions of the human upstream DNA were deleted and introduced into cells. The region responsive to EM fields is located between -353 and -1,257 relative to the P1 promoter.
Subject(s)
Electromagnetic Fields , Gene Expression Regulation/radiation effects , Genes, myc/radiation effects , Magnetics , Promoter Regions, Genetic/radiation effects , Animals , HeLa Cells , Humans , Mice , Multiple Myeloma , Proto-Oncogene Proteins c-myc/biosynthesis , Recombinant Fusion Proteins/biosynthesis , Transfection , Tumor Cells, CulturedABSTRACT
In its integrated form. SV-40 DNA offers an opportunity to observe the behavior of what is in effect a viral genome within a cellular genome, with transcriptional and translational products that can be clearly distinguished from those of the host cell. Exposure of SV40-transformed human fibroblasts to a 60 Hz continuous-wave sinusoidal electromagnetic (EM) field resulted in increased levels of virally derived mRNA and protein of large T-antigen. These findings provide evidence that a foreign DNA integrated into cells can be affected by EM fields under conditions known to cause increased transcripts from endogenous cellular genes.
Subject(s)
Antigens, Viral, Tumor/biosynthesis , Gene Expression/radiation effects , Magnetics , RNA, Messenger/biosynthesis , Simian virus 40/genetics , Blotting, Western , Cell Line , Cell Line, Transformed/radiation effects , Fibroblasts/metabolism , Fibroblasts/radiation effects , Humans , Transcription, Genetic/radiation effectsABSTRACT
There is strong public interest in the possibility of health effects associated with exposure to extremely low frequency (elf) electromagnetic (EM) fields. Epidemiological studies suggest a probable, but controversial, link between exposure to elf EM fields and increased incidence of some cancers in both children and adults. There are hundreds of scientific studies that have tested the effects of elf EM fields on cells and whole animals. A growing number of reports show that exposure to elf EM fields can produce a large array of effects on cells. Of interest is an increase in specific transcripts in cultured cells exposed to EM fields. The interaction mechanism with cells, however, remains elusive. Evidence is presented for a model based on cell surface interactions with EM fields.
