Expression pattern of a nuclear encoded mitochondrial arginine-ornithine translocator gene from Arabidopsis

• Main Authors: Schneider Anja, Kunze Reinhard, Wipf Daniel, Hilpert Melanie, Desimone Marcelo, Catoni Elisabetta, Flügge Ulf-Ingo, Schumacher Karin, Frommer Wolf B
• Format: Article
• Language: English
• Published: BMC 2003-01-01
• Series: BMC Plant Biology
• Online Access: http://www.biomedcentral.com/1471-2229/3/1

<p>Abstract</p> <p>Background</p> <p>Arginine and citrulline serve as nitrogen storage forms, but are also involved in biosynthetic and catabolic pathways. Metabolism of arginine, citrulline and ornithine is distributed between mitochondria and cytosol. For the shuttle of intermediates between cytosol and mitochondria transporters present on the inner mitochondrial membrane are required. Yeast contains a mitochondrial translocator for ornithine and arginine, Ort1p/Arg11p. Ort1p/Arg11p is a member of the mitochondrial carrier family (MCF) essential for ornithine export from mitochondria. The yeast <it>arg11 </it>mutant, which is deficient in Ort1p/Arg11p grows poorly on media lacking arginine.</p> <p>Results</p> <p>High-level expression of a nuclear encoded <it>Arabidopsis thaliana </it>homolog (AtmBAC2) of Ort1p/Arg11p was able to suppress the growth deficiency of <it>arg11</it>. RT-PCR analysis demonstrated expression of <it>AtmBAC2 </it>in all tissues with highest levels in flowers. Promoter-GUS fusions showed preferential expression in flowers, i.e. pollen, in the vasculature of siliques and in aborted seeds. Variable expression was observed in leaf vasculature. Induction of the promoter was not observed during the first two weeks in seedlings grown on media containing NH₄NO₃, arginine or ornithine as sole nitrogen sources.</p> <p>Conclusion</p> <p>AtmBAC2 was isolated as a mitochondrial transporter for arginine in Arabidopsis. The absence of expression in developing seeds and in cotyledons of seedlings indicates that other transporters are responsible for storage and mobilization of arginine in seeds.</p>