Abstract
Glutamine transporter has important roles on the glutamate-glutamine cycle in glutamatergic synapses of mammals. To examine glutamine-mediated regulation system on expression of nitrogen assimilatory genes in rice, we isolated a gene encoding the rat neuronal glutamine transporter (rGlnT) homologue from rice.
One rice cDNA (C10038) encoding rGlnT homologue was found by an EST-database search. This gene (OsGlnT) and its full-length cDNA were isolated by using PCR. The presumed transcribed region of OsGlnT gene, consisted of 6 exons separated by 5 introns, encodes 50 kDa protein, which has 11 hydrophobic membrane-spanning segments. Phylogenetic tree analysis showed that OsGlnT was clustered with mammal glutamine transporters (ATAs and SNs) but was not clustered with any plant amino acid transporters reported previously. OsGlnT transcript constantly accumulated in roots and leaves of rice plants. Further analyses of expression of OsGlnT and function of this gene product are now in progress.
