Peroxisomal targeting signals in green algae
- 321 Downloads
Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP–PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3′-diaminobenzidine. Our results confirm that the GFP–PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells.
KeywordsClosterium Green algae Peroxisomal targeting signal (PTS) Peroxisome Transport
We thank Dr Akira Kato for providing the cDNA of pumpkin citrate synthase and Dr. Yasuo Niwa (University of Shizuoka, Shizuoka) for providing the 35S-GFP(S65T) plasmid. This work was supported by a Grant for Promotion of Niigata University Research Projects.
- De Bellis L, Nishimura M (1991) Development of enzymes of the glyoxylate cycle during senescence of pumpkin cotyledons. Plant Cell Physiol 32:555–561Google Scholar
- Hayashi M, Toriyama K, Kondo M, Nishimura M (1998) 2,4-Dichlorophenoxybutyric acid-resistant mutants of Arabidopsis have defects in glyoxysomal fatty acid β-oxidation. Plant Cell 10:183–195Google Scholar
- Ichimura T (1971) Sexual cell division and conjugationpapilla formation in sexual reproduction of Closterium strigosum. In: Nishizawa K (ed) Proc 7th Int Seaweed Symp. University of Tokyo Press, Tokyo, pp 208–214Google Scholar
- Jansen GA, Ofman R, Ferdinandusse S, Ijlst L, Muijsers AO, Skjeldal OH, Stokke O, Jakobs C, Besley GTN, Wraith JE, Wanders RJA (1997) Refsum disease is caused by mutations in the phytanoyl-CoA hydroxylase gene. Nat Genet 17:190–193Google Scholar
- Kato A, Takeda-YoshikawaY, Hayashi M, Kondo M, Hara-Nishimura I, Nishimura M (1998) Glyoxysomal malate dehydrogenase in pumpkin: cloning of a cDNA and functional analysis of its presequence. Plant Cell Physiol 39:186–195Google Scholar
- Osumi T, Tsukamoto T, Hata S, Yokota S, Miura S, Fujiki Y, Hijikata M, Miyazawa S, Hashimoto T (1991) Amino-terminal presequence of the precursor of peroxisomal 3- ketoacyl- CoA thiolase is a cleavable signal peptide for peroxisomal targeting. Biochem Biophys Res Commun 181:947–954PubMedCrossRefGoogle Scholar
- Saito C, Ueda T, Abe H, Wada Y, Kuroiwa T, Hisada A, Furuya M, Nakano A (2002) A complex and mobile structure forms a distinct subregion within the continuous vacuolar membrane in young cotyledons of Arabidopsis. Plant J 29: 245–255Google Scholar
- Stabenau H (1974) Verteilung von microbody-enzyme aus Chlamydomonas in Dichtegradienten. Planta 118:35–42Google Scholar
- Stabenau H, Winkler U, Säftel W (1984) Mitochondrial metabolism of glycolate in the alga Eremosphaera viridis. Z Pflanzenphysiol 29:1377–1388Google Scholar