>Hello everybody - sorry so silent lately, but I've been studying for my
>prelim exam. While looking for papers related to my subject (vitamin D), I
>stumbled across a very recent article I wanted to share with you. The
>abstract follows:
>
>Magnetic Field Activation of Protein-DNA Binding
> Hana Lin, Li Han, Martin Blank, Mark Head, Reba Goodman
> Dept. Pathology, Columbia University Health Sciences, NY
>
> The mechanism involved in sensing, signaling, and coordinating changes
>resulting from magnetic field-induced stress show substantial similarities
>to those of heat shock, e.g., magnetic field-induced heat shock 70 gene
>(HSP70) expression involves heat shock factor (HSF) activation and heat
>shock element binding. However, an additional requirement for
>transactivation of HSP70 expression by magnetic fields is the binding of
Myc
>protein, indicating that additional elements and/or pathways are involved
in
>the induction of HSP70 expression by magnetic fields. To investigate the
>possible participation of additional genetic elements in magnetic
>field-induced HSP70 expression, we examined both magnetic field exposure
and
>heat shock on protein-DNA binding of the transcription factors HSF, AP-1,
>AP-2, and SP-1 in four human cell lines. The binding sites for these
>transcription factors are present in the HSP70 promoter. AP-1 binding
>activity, normally not increased by heat shock, was increased by magnetic
>fields; heat shock induced an increase only in HSF binding. Allthough
>intersecting and converging signalling pathways could account for the
>multiplicity of elements involved in magnetic field-induced HSP70
>transcription, direct interaction of magnetic fields with DNA is also a
>possible mechanism. Because magnetic fields penetrate the cell, they could
>well interact with conducting electrons present in the stacked bases of the
DNA.
>
>J. Cell. Biochem. 70:297-303, 1998
>
>
>
>Now that I thoroughly confused you all, let me break this down. HSP70 is a
>protein that binds to other proteins and targets them for degradation if
>they aren't made correctly. The induction of HSP70 can be caused by a
>number of factors, including excess heat (>40 degrees Celsius), chemicals,
>and UV radiation. Nature's rationale here is that all of these stimuli can
>cause cells to screw up when they are constructing proteins; these proteins
>have the potential to be lethal. Therefore, when the cell comes in contact
>with a toxic stimuli, it braces for damage by asking the DNA/RNA machiinery
>to make more HSPs.
>
>Now Dr. Goodmans group contends that magnetic fields can induce these HSPs
>as well. Furthermore, they contend that magnetic fields have the ability
to
>interact with the DNA DIRECTLY - that is, it bypasses all other cellular
>signalling factors and modulates DNA, thereby altering its cooperation with
>proteins, and altering the way certain genes are transcribed. This is
based
>on prior studies that implicate magnetic fields in DNA damage.
>
>Whats nice about this paper is that they back up this theory with actual
>data showing that more traditional signalling pathways are also activated
by
>magnetic fields. It wasn't stated in the text, but I think that these
>pathways might be stimulated by the alteration of membrane current, when
the
>magnetic field induces changes in ion flow across the cell membrane -
>especially calcium.
>
>We've evolved in a very low intensity magnetic field, though - so how much
>field constitutes the induction of cellular protection factors? Lin et al.
>says that the energy density (a measure of the energy required for induced
>stress) is about 14 orders of magnitude below that of heat shock - that is,
>the body is actually MORE sensitive to magnetic field fluctuations than it
>is to hyperthermia!!!!!
>
>methods:
>The magnetic fields used were 8 microtesla 60 Hz, pulsed for 20 min. The
cells
>were shielded from other, external fields. The cells were also monitored
>closely to ensure that the heat generated from the coil did not affect the
>cells.
>
>
>Hope this was educational for everybody - I know I was surprised!
>
>Dustin
>
>I promise to get that story about magnetic field induced weather patterns
on
>here as soon as I'm done with my exams!
>
>