Electromagnetic initiation of transcription at specific DNA sites

Initiation of transcription by electromagnetic (EM) fields offers an insigh t into mechanism. EM field stimulated transcription appears to require spec ific DNA sequences, and these bases may be sites where EM fields generate l arge repulsive forces between chains by accelerating electrons that move wi thin DNA. We can estimate the repulsion between chains by assuming that ele ctron affinity is a measure of electron density at each base, and inversely related to the velocity of electrons land the force). The repulsive force can be compared to the attraction between chains due to H-bonds. From the d ifference between repulsion and attraction, we show that sites rich in C an d T, as in the specific sequences, would be more likely to come apart in EM fields. These calculations suggest a plausible mechanism for initiation of transcription by EM fields, and provide a rationale for specific sequences to function as EM field response elements. Electron flow could also be a f actor in DNA chain melting due to joule heating. J. Cell. Biochem. 81 :689- 692, 2001. (C) 2001 Wiley-Liss, Inc.