Abstract
ATP-binding cassette (ABC) proteins constitute a large superfamily ranging from bacteria to human. Arabidopsis thaliana genome contains a total of 131 open reading frames (ORFs) that encode ABC proteins. AtABCA1 in Arabidopsis, the human ABCA1 functioning as a major regulator of cellular cholesterol homeostasis, is a single copy gene in the genome. Its orthologue is't found in yeast and even in rice, which suggests that AtABCA1 has physiological functions specific to dicots in plants. In this study we have isolated full-length AtABCA1 cDNA and carried out the expression analysis of AtABCA1 gene. Northern analysis of AtABCA1 in Arabidopsis revealed that AtABCA1 expressed in all organs, especially in the stem and the root. GUS plant analysis showed AtABCA1 was only expressed in the vascular tissues of root, stem, and leaf through the seedling and the adult plant. These results suggest that AtABCA1 is involved in the long-distance transport of endogenous substances.
