The effect of 50 Hz magnetic field on GCSmRNA expression in lymphoma B cell by mRNA differential display

Magnetic fields (MFs) of various characteristics can lead to plethora effec ts in biological system. From a molecular point of view, we hypothesized th at there must be a fundamental difference in gene expression between the MF exposed and the unexposed cell. To identify the classes of genes that are regulated, 0.8 mT 50 Hz MF-induccd changes in gene expression were examined in a Daudi cell culture using differential display and reverse transcripta se-polymerase chain reaction. A candidate cDNA (signatured as MF-CB) that w as observed in the sham-exposed but not in MF-exposed cultures was recovere d and reamplified. After verification by Northern blot, the cDNA was cloned and sequenced. It was found that 254-base pair of 5'-end MF-CB cDNA clone was identical to gcs in open reading frame (ORF) range. Based on the prelim inarily sequence, the prolonged length of 5'-end MF-CB cDNA was obtained by PCR amplification and its sequence analysis showed the same results as its original fragment. In order to further determine whether MF-CB cDNA is fro m gcs, two Northern blots were probed with gcs and MF-CB cDNA, respectively , and the data revealed signals of the same size and expression pattern on the two probe filters, which demonstrated that MF-CB is an EST (expression sequence tag) of gcs. gcs is a gene, identified recently (GenBank accession number D89866), encoding ceramide glucosyltransferase (CCS), which has bee n implicated as a causal element in human cell growth and differentiation. In an additional experiment, time-dependent changes in the transcription of gcs induced by 0.8 mT MF were observed by Northern blot with a sharp and r eproducible inhibition effect after 20 min exposure and a reduction after 2 0-24 h exposure. The study demonstrates for the first time that 50 Hz MF ca n lead to changes in gcs transcription, which provides a new clue to elucid ate the mechanism by which MF influence cell growth and differentiation. (C ) 2000 Wiley-Liss, Inc.