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United States Department of Agriculture

Agricultural Research Service

Title: Localization of ZnT7 and zinc ions in mouse retina-Immunohistochemistry and selenium autometallography

Authors
item Wang, Xin - CHINA MEDICAL UNIVERSITY
item Wang, Zhan-You - CHINA MEDICAL UNIVERSITY
item Gao, Hui-Ling - CHINA MEDICAL UNIVERSITY
item Danscher, Gorm - UNIV. OF AARHUS DENMARK
item Huang, Liping

Submitted to: Brain Research
Publication Type: Other
Publication Acceptance Date: December 1, 2006
Publication Date: December 10, 2006
Citation: Wang, X., Wang, Z., Gao, H., Danscher, G., Huang, L. Localization of ZnT7 and zinc ions in mouse retina-Immunohistochemistry and selenium autometallography. Brain Research Bulletin, 2006.71:91-96

Interpretive Summary: The ZnT7 protein, a zinc transporter, is involved in carrying zinc ions from the cytoplasm of the cell into the Golgi apparatus. The cytoplasm is a jelly like material that is made up of mostly water and various organelles, such as the Golgi apparatus, as well as salts, dissolved gasses and nutrients. It is between the cell membrane and the nuclear envelope. The primary function of the Golgi apparatus is to process and package macromolecules (proteins and lipids) synthesized by the cell. In the present study, we examined the distribution and localization of ZnT7 and the labile zinc ions in the mouse retina, a thin layer of neural cells that lines the back of the eyeball, using immunohistochemistry and in vivo zinc–selenium autometallography (ZnSeAMG). Our results showed that ZnT7 is abundantly expressed in the ganglion cells (optical neurons) and pigment epithelial cells (nurturing cells). ZnT7 is also expressed in the amacrine cells (interneurons) and the layer of optic fibers of the mouse retina, but to a lesser extent. Weak staining of ZnT7 was detected in the inner plexiform layer (fibrils formed by the ganglion cells), outer plexiform layer (layer of neuronal synapses), and outer segment of the photoreceptors. However, ZnT7 was not detected in the outer nuclear layer (layer of oval nuclear bodies) and inner segment of the photoreceptors. A high level of labile zinc pool was detected in the pigment epithelial cells, the inner segment of the photoreceptors, and the marginal region of the inner nuclear layer. Less amount of labile zinc ions were detected in the ganglion cells of the retina. These observations strongly suggest that ZnT7 may play critical roles in retinal zinc homeostasis and that loosely-bound zinc pools may have multiple functions in the retina.

Technical Abstract: Zinc transporter 7 (ZnT7, Slc30a7), a member of the Slc30 family, is involved in mobilizing zinc ions from the cytoplasm into the Golgi apparatus. In the present study, we examined the distribution and localization of ZnT7 and the labile zinc ions in the mouse retina using immunohistochemistry and in vivo zinc–selenium autometallography (ZnSeAMG). Our results showed that ZnT7 is abundantly expressed in the ganglion cells and pigment epithelial cells of the mouse retina. ZnT7 is also expressed in the amacrine cells and the layer of optic fibers of the mouse retina, but to a lesser extent.Weak staining of ZnT7 was detected in the inner plexiform layer, outer plexiform layer, and outer segment of the photoreceptors. However, ZnT7 was not detected in the outer nuclear layer and inner segment of the photoreceptors. A high level of labile zinc pool was detected in the pigment epithelial cells, the inner segment of the photoreceptors, and the marginal region of the inner nuclear layer. Less amount of labile zinc ions were detected in the ganglion cells of the retina. These observations strongly suggest that ZnT7 may play critical roles in retinal zinc homeostasis and that chelatable zinc pools may have multiple functions in the retina.

Last Modified: 8/27/2014
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