Abstract
Arabidopsis genome contains ca. 130 ATP-binding cassette (ABC) protein genes. AtABCA1 of Arabidopsis, the counterpart of human ABCA1 functioning as a major regulator of cellular cholesterol homeostasis, is a single copy gene, whereas its orthologue is not found in yeast and even in rice genome. This occurrence suggests that AtABCA1 has physiological functions specific to dicots, or other members of ABC protein may complement the roles of ABCA1 in monocots. In this study we analyzed the gene expression of AtABCA1. The AtABCA1 expression was specifically up-regulated by abscisic acid. AtABCA1 promoter::GUS trasngenic plants showed that AtABCA1 preferentially expressed in the vascular tissues of root, stem, and leaf through out the growth stage from seedling to adult plant. In addition, strong expression was also observed in mature pollen. We are determining the subcellular localization of AtABCA1 by use of GFP-fusion protein expressed in Arabidopsis stable transformant.
