title: Identification of the putative goldfish (Carassius auratus) magnesium transporter SLC41a1 and functional regulation in the gill, kidney, and intestine in response to dietary and environmental manipulations.
abstract: While magnesium requirements for teleost fish highlight the physiological importance of this cation for homeostasis, little is known regarding the molecular identity of transporters responsible for magnesium absorption or secretion. The recent characterization of the vertebrate magnesium transporter solute carrier 41a1 (SLC41a1) in the kidney of a euryhaline fish has provided a glimpse of possible moieties involved in piscine magnesium regulation. The present study obtained a novel SLC41a1 coding sequence for Carassius auratus and demonstrated ubiquitous expression in all tissues examined. Transcriptional regulation of SLC41a1 in response to dietary and environmental magnesium concentrations was observed across tissues. Specifically, decreased environmental magnesium correlated with decreased expression of SLC41a1 in the intestine, whereas the gill and kidney were unaffected. Dietary magnesium restriction correlated with decreased expression of SLC41a1 in the intestine and gill, while again no effects were detected in the kidney. Finally, elevated dietary magnesium correlated with increased expression of SLC41a1 in the kidney, while expression in the intestine and gill remained stable. Plasma magnesium was maintained in all treatments, and dietary assimilation efficiency increased with decreased dietary magnesium. Consumption of a single meal failed to impact SLC41a1 expression, and transcript abundance remained stable over the course of digestion in all treatments. Transcriptional regulation occurred between 7 and 14days following dietary and environmental manipulations and short-term regulation (e.g. <24h) was not observed. Overall the data supports transcriptional regulation of SLC41a1 reflecting a possible role in magnesium loss or secretion across tissues in fish.
authors.affiliation: York University, Department of Biology, 4700 Keele Street, Toronto, M3J 1P3, ON, Canada.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kodzhahinchev
authors.affiliation: York University, Department of Biology, 4700 Keele Street, Toronto, M3J 1P3, ON, Canada.
authors.forename: Drago
authors.initials: D
authors.lastname: Kovacevic
authors.affiliation: York University, Department of Biology, 4700 Keele Street, Toronto, M3J 1P3, ON, Canada. Electronic address: cbucking@yorku.ca.
authors.forename: Carol
authors.initials: C
authors.lastname: Bucking
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D004032:Diet / Q000662:veterinary*; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005880:Gills / Q000254:growth & development / Q000378:metabolism*; D006054:Goldfish / Q000097:blood / Q000254:growth & development / Q000502:physiology*; D007413:Intestinal Mucosa / Q000254:growth & development / Q000378:metabolism*; D007422:Intestines / Q000254:growth & development; D007668:Kidney / Q000254:growth & development / Q000378:metabolism*; D008274:Magnesium / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D009928:Organ Specificity; D010802:Phylogeny; D011897:Random Allocation; D016415:Sequence Alignment; D013997:Time Factors; D060753:Water Quality
chemical_list: D027682:Cation Transport Proteins; D029941:Fish Proteins; D008274:Magnesium
keywords: Digestion; Freshwater; Ion poor water; Ion regulation; Magnesium; SLC41a1; Stenohaline