Skip to main content
ARS Home » Research » Publications at this Location » Publication #71659
Title: CLONING A LYSINE AMINO ACID TRNASPORTER

Author
item CHEN, LISCHEN - PLANT BIOLOGY UOFI URBANA
item Bush, Daniel

Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Lysine is a low abundance amino acid in the endosperm of many agriculturally important cereals, such as barley and maize. This deficiency compromises the nutritional value of these crops. We report here the cloning and characterization of an Arabidopsis lysine transporter from the EST library by functional complementation in yeast. Although this clone shares some homology to the NAT2/AAP gene family, it represents a new class of amino acid transporters. The cDNA encodes a highly hydrophobic protein with nine putative transmembrane domains. The primary substrate of this carrier is lysine with an apparent Km of 175uM. While this porter can also transport histidine (apparent Km of 393uM), it does not transport arginine. This is in contrast to another, unrelated, cationic amino acid carrier also identified in Arabidopsis (PNAS 92:12036). Southern blot analysis suggests this is a single copy gene in the Arabidopsis genome. RNA gel blot analysis showed that its strongest expression is in root and silique tissues. Whole mount in situ hybridizations in young seedlings showed root expression is primarily restricted to the root surface. We are currently investigating the activity of this porter in a lysine transport mutant of carrot. Transgenic expression is also being used to explore the impact of this transporter on plant nitrogen content.