title: Gene organization and expression of the divalent cation transporter Nramp in the protistan parasite Perkinsus marinus.
abstract: Trophozoites of the protistan parasite Perkinsus marinus reside and proliferate inside phagosomelike structures of hemocytes from the host, the eastern oyster Crassostrea virginica. In a murine model, it has been proposed that the outcome of intracellular parasite-host interactions is determined, at least in part, by the activity of the host's divalent cation transporter natural resistance-associated macrophage protein 1 (Nramp1). Although nucleotide sequences from members of the Nramp family in protozoan parasites have recently become available in public databases, little is known about their molecular, structural, and functional aspects that may relate to the parasite's survival of intracellular killing by the host. The complementary DNA (cDNA) sequence of the Nramp from P. marinus (PmNramp) was obtained by polymerase chain reaction amplification with degenerated primers, followed by rapid amplification of cDNA ends. The 2,082-bp cDNA sequence encoded a predicted protein of 558 amino acids. PmNramp is a single-copy gene composed of 7 exons and 6 short introns (44-61 bp) with the canonical splicing signal (GT/AG). A phylogenetic analysis indicates that P. marinus and apicomplexan Nramp genes derive from a common "archetype" Nramp ancestor. However, the apicomplexan Nramps are highly divergent from the P. marinus sequence and the rest of the archetype Nramp group. Preliminary studies suggest that expression of PmNramp in in vitro-cultured P. marinus trophozoites is modulated by metals and by exogenous oxidative stress.
authors.affiliation: Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202-3101, USA.
authors.forename: José-Antonio F
authors.initials: JA
authors.lastname: Robledo
authors.forename: Pascal
authors.initials: P
authors.lastname: Courville
authors.forename: Mathieu F M
authors.initials: MF
authors.lastname: Cellier
authors.forename: Gerardo R
authors.initials: GR
authors.lastname: Vasta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry; D056890:Eukaryota / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D016415:Sequence Alignment; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D027682:Cation Transport Proteins; D018076:DNA, Complementary; D016054:DNA, Protozoan; D006861:Hydrogen Peroxide; D016877:Oxidants; D016053:RNA, Protozoan; D000099173:Natural Resistance-associated Macrophage Protein 1