Abstract
Arabidopsis genome contains approximately 130 ABC protein genes. Despite the complete amino acid sequence data, little is known about the endogenous substrates of these ABC proteins, in particular for P-glycoprotein-like (PGP) subfamily. In this study, we analyzed the gene expression of AtPGP4, a PGP type ABC protein in Arabidopsis thaliana. Northern analysis of Atpgp4 in intact plant showed that Atpgp4 was preferentially expressed in the root. Transgenic plants carrying the upstream sequence (2.2 kb) of Atpgp4 fused to the β-glucuronidase (GUS) as a reporter were histochemically stained at different stages of the development. The roots were strongly stained, and the tips of leaf serration and silique junctions were also moderately stained. Moreover, the gene expression of AtPGP4 positively regulated by cytokinins but not by auxins. We are now analyzing the transgenic plants, in which Atpgp4 is overexpressed, in comparison with T-DNA tag line.
