title: ZnT7, a novel mammalian zinc transporter, accumulates zinc in the Golgi apparatus.
abstract: ZnT7, a novel member of the zinc transporter (ZnT) family, was identified by searching the expressed sequence tag (EST) databases with the amino acid sequence of ZnT1. Like the other ZnT proteins, the protein (387 amino acids) predicted from this gene contains six transmembrane domains and a histidine-rich loop between transmembrane domains IV and V. We show that Znt7 is widely transcribed in mouse tissues with abundant expression in the liver and small intestine and moderate expression in the kidney, spleen, brain, and lung. An affinity-purified antibody raised against the amino acids 299-315 of mouse ZnT7 specifically reacted with the proteins with apparent molecular masses of 85, 43, and 65 kDa in small intestine and lung tissues by Western blot analysis. Immunofluorescence microscope analysis reveals that ZnT7 is localized in the Golgi apparatus and cytoplasmic vesicles. Exposure of the ZnT7-expressing Chinese hamster ovary (CHO) cells to zinc causes an accumulation of zinc in the Golgi apparatus, suggesting that ZnT7 facilitates zinc transport from the cytoplasm into the Golgi apparatus.
authors.affiliation: Western Human Nutrition Research Center, Agriculture Research Service, United States Department of Agriculture, Davis, California 95616, USA.
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Kirschke
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002451:Cell Compartmentation; D006224:Cricetinae; D017931:DNA Primers; D020224:Expressed Sequence Tags; D006056:Golgi Apparatus / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015032:Zinc / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D017931:DNA Primers; D012333:RNA, Messenger; C472294:SLC30A7 protein, human; C472293:ZnT7 protein, mouse; C017800:zinc-binding protein; D015032:Zinc