The mitochondrial fission regulator DRP3B does not regulate cell death in plants.
OBJECTIVE
Recent reports have described dramatic alterations in mitochondrial morphology during metazoan apoptosis. A dynamin-related protein (DRP) associated with mitochondrial outer membrane fission is known to be involved in the regulation of apoptosis. This study analysed the relationship between mitochondrial fission and regulation of plant cell death.


METHODS
Transgenic plants were generated possessing Arabidopsis DRP3B (K56A), the dominant-negative form of Arabidopsis DRP, mitochondrial-targeted green fluorescent protein and mouse Bax.


RESULTS
Arabidopsis plants over-expressing DRP3B (K56A) exhibited long tubular mitochondria. In these plants, mitochondria appeared as a string-of-beads during cell death. This indicates that DRP3B (K56A) prevented mitochondrial fission during plant cell death. However, in contrast to results for mammalian cells and yeast, Bax-induced cell death was not inhibited in DRP3B (K56A)-expressing plant cells. Similarly, hydrogen peroxide-, menadione-, darkness- and salicylic acid-induced cell death was not inhibited by DRP3B (K56A) expression.


CONCLUSIONS
These results indicate that the systems controlling cell death in animals and plants are not common in terms of mitochondrial fission.
Institute of Molecular and Cellular Biosciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-0032, Japan.
Keiko
K
Yoshinaga
Masaru
M
Fujimoto
Shin-Ichi
S
Arimura
Nobuhiro
N
Tsutsumi
Hirofumi
H
Uchimiya
Maki
M
Kawai-Yamada
D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D016923:Cell Death / Q000502:physiology; D020558:GTP Phosphohydrolases / Q000502:physiology*; D008928:Mitochondria / Q000502:physiology; D009154:Mutation; D030821:Plants, Genetically Modified / Q000502:physiology; D026361:Reactive Nitrogen Species / Q000502:physiology; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein / Q000502:physiology
D029681:Arabidopsis Proteins; D026361:Reactive Nitrogen Species; D051028:bcl-2-Associated X Protein; C456288:ADL2b protein, Arabidopsis; D020558:GTP Phosphohydrolases