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Processing of ATG8s, ubiquitin-like proteins, and their deconjugation by ATG4s are essential for plant autophagy
- Source :
- Plant Cell. 16(No. 11):2967-2983
- Publication Year :
- 2004
-
Abstract
- Autophagy is an intracellular process for vacuolar degradation of cytoplasmic components. Thus far, plant autophagy has been studied primarily using morphological analyses. A recent genome-wide search revealed significant conservation among autophagy genes ( ATG s) in yeast and plants. It has not been proved, however, that Arabidopsis thaliana ATG genes are required for plant autophagy. To evaluate this requirement, we examined the ubiquitination-like Atg8 lipidation system, whose component genes are all found in the Arabidopsis genome. In Arabidopsis, all nine ATG8 genes and two ATG4 genes were expressed ubiquitously and were induced further by nitrogen starvation. To establish a system monitoring autophagy in whole plants, we generated transgenic Arabidopsis expressing each green fluorescent proteināATG8 fusion (GFP-ATG8). In wild-type plants, GFP-ATG8s were observed as ring shapes in the cytoplasm and were delivered to vacuolar lumens under nitrogen-starved conditions. By contrast, in a T-DNA insertion double mutant of the ATG4 s ( atg4a4b-1 ), autophagosomes were not observed, and the GFP-ATG8s were not delivered to the vacuole under nitrogen-starved conditions. In addition, we detected autophagic bodies in the vacuoles of wild-type roots but not in those of atg4a4b-1 in the presence of concanamycin A, a V-ATPase inhibitor. Biochemical analyses also provided evidence that autophagy in higher plants requires ATG proteins. The phenotypic analysis of atg4a4b-1 indicated that plant autophagy contributes to the development of a root system under conditions of nutrient limitation.
- Subjects :
- DNA, Bacterial
Vacuolar Proton-Translocating ATPases
Nitrogen
Recombinant Fusion Proteins
ATG8
Transgene
Arabidopsis
Plant Science
Vacuole
Plant Roots
Microscopy, Electron, Transmission
Gene Expression Regulation, Plant
Autophagy
Arabidopsis thaliana
Enzyme Inhibitors
Gene
Research Articles
biology
Arabidopsis Proteins
Ubiquitin
Genetic Complementation Test
Gene Expression Regulation, Developmental
Cell Biology
Plants, Genetically Modified
biology.organism_classification
Cell biology
Biochemistry
Cytoplasm
Mutation
Vacuoles
Microtubule-Associated Proteins
Subjects
Details
- Language :
- English
- Volume :
- 16
- Issue :
- No. 11
- Database :
- OpenAIRE
- Journal :
- Plant Cell
- Accession number :
- edsair.doi.dedup.....9c1ffc1507af5baf3629b067c81a4ef1