Evidence
That the ZNT3 Protein Controls the Total Amount of Elemental Zinc in
Synaptic Vesicles
David H. Linkous, Jane M. Flinn, Jae Y. Koh, Antonio Lanzirotti, Paul
M. Bertsch,
Blair F. Jones, Leonard J. Giblin, and Christopher J. Frederickson
Department of Psychology, George Mason University, Fairfax, Virginia
(DHL,JMF); Department of Neurology, University of Ulsan College of Medicine,
Poongnapdong, Songpagu, Seoul, South Korea (JYK); Consortium for Advanced
Radiation Sources, University of Chicago, Chicago, Illinois (AL); National
Synchrotron Light Source, Brookhaven National Laboratory, Upton, New
York (AL); Savannah River Ecology Laboratory, University of Georgia,
Aiken, South Carolina (PMB); United States Geological Survey, Reston,
Virginia (BFJ); and NeuroBioTex, Inc., Galveston, Texas (LJG,CJF)
Abstract:
The ZNT3 protein decorates the presynaptic vesicles of central neurons
harboring vesicular zinc, and deletion of this protein removes staining
for zinc. However, it has been unclear whether only histochemically reactive
zinc is lacking or if, indeed, total elemental zinc is missing from neurons
lacking the Slc30a3 gene, which encodes the ZNT3 protein. The limitations
of conventional histochemical procedures have contributed to this enigma.
However, a novel technique, microprobe synchrotron X-ray fluorescence,
reveals that the normal 2- to 3-fold elevation of zinc concentration normally
present in the hippocampal
mossy fibers is absent in Slc30a3 knockout (ZNT3) mice. Thus, the
ZNT3 protein evidently controls not only the “stainability”
but also the actual mass of zinc in mossy-fiber synaptic vesicles. This
work thus confirms the metal-transporting role of the ZNT3 protein in
the brain.
Key
words: mossy fibers, ZNT3, glutamate, zinc release, hilus, X-ray,
fluorescence, knockout
SREL Reprint #3063
Linkous,
D. H., J. M. Flinn, J. Y. Koh, A. Lanzirotti, P. M. Bertsch, B. F. Jones,
L. J. Giblin, and C. J. Frederickson. 2008. Evidence That the ZNT3 Protein
Controls the Total Amount of Elemental Zinc in Synaptic Vesicles. Journal
of Histochemistry and Cytochemistry 56(1): 3-6.
