title: A novel variant of aquaporin 3 is expressed in killifish (Fundulus heteroclitus) intestine.
abstract: Killifish (Fundulus heteroclitus) are euryhaline teleosts that are widely used in environmental and toxicological studies, and they are tolerant to arsenic, in part due to very low assimilation of arsenic from the environment. The mechanism of arsenic uptake by the intestine, a major route of arsenic uptake in humans is unknown. Thus, the goal of this study was to determine if aquaglyceroporins (AQPs), which transport water and other small molecules including arsenite across cell membranes, are expressed in the killifish intestine, and whether AQP expression is affected by osmotic stress. Through RT-PCR and sequence analysis of PCR amplicons, we demonstrated that the intestine expresses kfAQP3a and kfAQP3b, two previously identified variants, and also identified a novel variant of killifish AQP3 (kfAQP3c) in the intestine. The variants likely represent alternate splice forms. A BLAST search of the F. heteroclitus reference genome revealed that the AQP3 gene resides on a single locus, while an alignment of the AQP3 sequence among 384 individuals from eight population ranging from Rhode Island to North Carolina revealed that its coding sequence was remarkably conserved with no fixed polymorphism residing in the region that distinguishes these variants. We further demonstrate that the novel variant transports arsenite into HEK293T cells. Whereas kfAQP3a, which does not transport arsenite, was expressed in both freshwater (FW) and saltwater (SW) acclimated fish, kfAQP3b, an arsenic transporter, was expressed only in FW acclimated fish, and kfAQP3c was expressed only in SW acclimated fish. Thus, we have identified a novel, putative splice variant of kfAQP3, kfAQP3c, which transports arsenic and is expressed only in SW acclimated fish.
authors.affiliation: Department of Microbiology and Immunology and of Physiology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA. Electronic address: Dawoon.Jung@Dartmouth.Edu.
authors.forename: Dawoon
authors.initials: D
authors.lastname: Jung
authors.affiliation: Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA.
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Adamo
authors.affiliation: Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Lehman
authors.affiliation: Department of Microbiology and Immunology and of Physiology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
authors.forename: Roxanna
authors.initials: R
authors.lastname: Barnaby
authors.affiliation: The School of Public and Environmental Affairs, Indiana University, Bloomington, IN 47405, USA.
authors.forename: Craig E
authors.initials: CE
authors.lastname: Jackson
authors.affiliation: Department of Earth Sciences and Chemistry, Dartmouth College, Hanover, NH 03755, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Jackson
authors.affiliation: Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA; The School of Public and Environmental Affairs, Indiana University, Bloomington, IN 47405, USA; School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Shaw
authors.affiliation: Department of Microbiology and Immunology and of Physiology, The Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Stanton
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D051400:Aquaporin 3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport; D017124:Conserved Sequence; D063366:Estuaries; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D023781:Fundulidae / Q000254:growth & development / Q000502:physiology*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008281:Maine; D008969:Molecular Sequence Data; D009511:New England; D064587:Osmoregulation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D054712:Salinity; D016415:Sequence Alignment; D015144:Southeastern United States; D013312:Stress, Physiological
chemical_list: D018053:Arsenites; D029941:Fish Proteins; D011994:Recombinant Proteins; D051400:Aquaporin 3; C015001:arsenite
keywords: Aquaglyceroporin; Arsenite uptake; Fundulus heteroclitus; Intestine; Salinity