Abstract
Peroxisomes play important roles for lipid degradation and photorespiration. We have isolated Arabidopsis mutants that show resistance to toxic level of 2,4-dicholorophenoxybutyric acid. Analyses of the mutants allowed us to identify three genes, PED1, PED2 and PED3, that are essential for lipid degradation in peroxisomes.
Of these, a PED3 gene encodes Ped3p, a 149-kD protein that exists in peroxisomal membranes. The amino acid sequence of the Ped3p had a typical characteristic for "full-size" ATP-binding cassette (ABC) transporter consisting of two transmembrane regions and two ATP-binding regions. Peroxisomes in ped3 mutant lose activity for lipid degradation, but show normal morphology. In contrast, ped1 mutant with defective 3-ketoacyl CoA thiolase gene has peroxisomes with abnormal morphology. ped1/ped3 double mutant has severe defect in morphology of leaves and inflorescence, and becomes sterile.
We will discuss function of Ped3p on lipid degradation and morphogenesis.
