Poster: Late and Moved Abstracts

Abs # 1391: Ultrastructural Observation of aberrant peroxisome morphology (apm) Mutants of Arabidopsis

Presenter:	Kondo, Maki , maki@nibb.ac.jp
Authors	Kondo, Maki  (A)   Mano, Shoji  (A) (B)  Nakamori, Chihiro  (A)   Nishimura, Mikio  (A) (B)
Affiliations:	(A): National Institute for Basic Biology (B): Dept.Mol.Biomechanics,Graduate Univ. Advansed Studies

Peroxisomes are ubiquitous organelles that are found in eukaryotic cells. In higher plants, peroxisomes have vital roles during plant life cycles. The mechanisms of protein targeting to peroxisomes and functional transition of peroxisomes have been investigated in higher plants, but little is known about biogenesis of peroxisomes. To investigate biogenesis of peroxisomes, we visualized peroxisomes using green fluorescent protein (GFP) combined with peroxisomal targeting signal 1 (PTS1) in Arabidopsis. Transgenic Arabidopsis seeds, designated GFP-PTS1, that express the chimeric protein consisting of GFP and PTS1 were mutagenized to screen the mutants having abnormal peroxisome morphology. These mutants, designated aberrant peroxisome morphology (apm), exhibited the tissue- and/or organ-specific patterns of GFP as follows, (i) long peroxisomes, (ii) giant peroxisomes, (iii) GFP fluorescence in the cytosol as well as in peroxisomes, and (iv) different distribution. Immunoelectron microscopic analysis shows that GFP and catalase, a peroxisomal marker enzyme, were co-localized in the same organelle in these apm mutants, and that the morphology of such organelle was almost the same as that detected in the GFP fluorescence. In this presentation, we report about ultrastructural observation of apm mutants and organ-specificity of aberrant peroxisomal morphology in comparison with those of GFP-PTS1.