Meeting Abstract
29.2 Wednesday, Jan. 5 Genes underlying amino acid transport differences in echinoderms from contrasting polar and temperate environments. APPLEBAUM, S.L.*; GINSBURG, D.W.; MANAHAN, D.T.; University of Southern California; University of Southern California; University of Southern California sappleba@usc.edu
Many phyla of marine invertebrates absorb dissolved organic material across their body walls from low concentrations in seawater. For dissolved amino acids, the specific transporters that regulate their trans-membrane flux play a role in diverse physiological processes, including nutrition, osmo-regulation, and chemo-reception. Our laboratory has recently characterized amino acid transporter genes in a temperate species of sea urchin. The goal of the current study was to determine whether the same gene family was present in echinoderms from an extreme-cold environment (Antarctica). Conserved regions of known transporter genes in the sodium dependent amino acid/neurotransmitter transporter family (SLC6) were used to design degenerate primers and PCR-amplify similar sequences from the RNA of six species collected in McMurdo Sound. Collectively, 10 partial mRNA sequences of putative amino acid transporters were isolated from Acodontaster hodgsoni (Ah), Diplasterias brucei (Db), Odontaster meridionalis (Om), Odontaster validus (Ov), Perknaster fuscus (Pf) and Sterechinus neumayeri (Sn). In adult Ah, Pf, Om and Sn, the expression of these genes was detected in tube feet, gonad, and digestive tissues. Their expression was also detected in early developmental stages (embryos and larvae, Ah; larvae, Om). Members of the SLC6 gene family appear widespread among Antarctic echinoderms. The expression of these genes in early developmental stages opens up the possibility of linking previous studies of nutritional ecophysiology with an understanding of the molecular biological mechanisms of transport. This will allow for a mechanistic understanding of existing observations of high amino acid transport rates from low concentrations found in Antarctic seawaters.
