title: Soybean ascorbate peroxidase suppresses Bax-induced apoptosis in yeast by inhibiting oxygen radical generation.
abstract: Bax, a mammalian proapoptotic member of the Bcl-2 family, can induce cell death when expressed in yeast or plant cells. To identify plant Bax inhibitors, we cotransformed a soybean cDNA library and the Bax gene into yeast cells and screened for expressed genes that prevented Bax-induced apoptosis. From the Bax-inhibiting genes isolated, ascorbate peroxidase (sAPX) was selected for characterization. The transcription of sAPX in plants was specifically induced by oxidative stress. Moreover, overexpression of sAPX partially suppressed the H(2)O(2)-sensitive phenotype of yeast cytosolic catalase T (Deltactt)- and thermosensitive phenotype of cytochrome c peroxidase (Deltaccp)-deleted mutant cells. Examination of reactive oxygen species (ROS) production using the fluorescence method of dihydrorhodamine 123 oxidation revealed that expression of Bax in yeast cells generated ROS, which was greatly reduced by coexpression with sAPX. Our results collectively suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Bax-induced cell death in yeast.
authors.affiliation: Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Haejeong
authors.initials: H
authors.lastname: Moon
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.forename: Boyoung
authors.initials: B
authors.lastname: Lee
authors.forename: D Theertha
authors.initials: DT
authors.lastname: Prasad
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Moo Je
authors.initials: MJ
authors.lastname: Cho
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
authors.forename: Myung Suk
authors.initials: MS
authors.lastname: Choi
authors.forename: Jeongdong
authors.initials: J
authors.lastname: Bahk
authors.forename: Myeong Ok
authors.initials: MO
authors.lastname: Kim
authors.forename: Jong Chan
authors.initials: JC
authors.lastname: Hong
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
mesh_terms: D017209:Apoptosis; D060387:Ascorbate Peroxidases; D015152:Blotting, Northern; D015153:Blotting, Western; D002374:Catalase / Q000502:physiology; D016923:Cell Death; D003001:Cloning, Molecular; D003578:Cytochrome-c Peroxidase / Q000502:physiology; D018076:DNA, Complementary / Q000378:metabolism; D005434:Flow Cytometry; D015723:Gene Library; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D018384:Oxidative Stress; D010544:Peroxidases / Q000494:pharmacology*; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species; D012235:Rhodamines / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013025:Glycine max / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors; D014158:Transcription, Genetic; D051028:bcl-2-Associated X Protein
chemical_list: D018076:DNA, Complementary; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012235:Rhodamines; D051028:bcl-2-Associated X Protein; C058319:dihydrorhodamine 123; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D003578:Cytochrome-c Peroxidase; D002374:Catalase