Cloned (Comment) | Organism |
---|---|
gene APX6, quantitative RT-PCR enzyme expression analysis, transient expression assays in Nicotiana benthamiana leaves, constitutive expression of APX6 is restricted to old and dying cells and absent in younger tissues, thus age-dependent post-transcriptional regulation of APX6. The coding sequence of APX6 is a potential target of miR398, which is a key regulator of copper redistribution | Arabidopsis thaliana |
Protein Variants | Comment | Organism |
---|---|---|
additional information | expression analysis of cytosolic APX isozymes in recombinant Nicotiana benthamiana shows that only APX6 displays a gradual increase in expression along the leaf blade with about a 4 and a 30fold higher level in the mid and tip sections, respectively, compared with the base. The changes in the level of APX6 correlate with the changes in the expression of the senescence marker gene SAG12. The age-dependent activation of the APX6 promoter is proven by APX6pro::GUS expression in leaves at different ages of the plants, phenotypes, detailed overview | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
cytosol | - |
Arabidopsis thaliana | 5829 | - |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Fe2+ | in the heme group | Arabidopsis thaliana |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 L-ascorbate + H2O2 + 2 H+ | Arabidopsis thaliana | - |
L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q8GY91 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
additional information | age-dependent post-transcriptional regulation of APX6 | Arabidopsis thaliana |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
leaf | APX6 is nearly 4fold higher in late senescing leaves of 6.5-week-old plants compared with young green leaves of 4-week-old plants | Arabidopsis thaliana | - |
additional information | the constitutive expression of APX6 is restricted to old and dying cells and absent in younger tissues | Arabidopsis thaliana | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 L-ascorbate + H2O2 + 2 H+ | - |
Arabidopsis thaliana | L-ascorbate + L-dehydroascorbate + 2 H2O | - |
? |
Synonyms | Comment | Organism |
---|---|---|
APX6 | - |
Arabidopsis thaliana |
ascorbate peroxidase6 | - |
Arabidopsis thaliana |
AtAPx08 | - |
Arabidopsis thaliana |
L-ascorbate peroxidase 6 | - |
Arabidopsis thaliana |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
heme | - |
Arabidopsis thaliana |
Organism | Comment | Expression |
---|---|---|
Arabidopsis thaliana | identification of potential small RNAs involved in regulating APX6 level, overview | additional information |
Arabidopsis thaliana | APX6 is a bona fide senescence-associated gene. High osmotic conditions, dark stress, and abscisic acid (ABA) activate APX6 expression in an age-dependent manner. APX6 expression is specifically induced in aging leaves and in response to senescence-promoting stimuli such as abscisic acid (ABA), extended darkness, and osmotic stress. apx6 mutants showed early developmental senescence and increased sensitivity to dark stress. Mutants of squamosa promoter binding protein-like7 (SPL7), the master regulator of copper homeostasis and miR398 expression, have a higher APX6 level compared to the wild-type, which further increases under copper deficiency. miR398 is a potential post-transcriptional regulator of APX6 | up |
General Information | Comment | Organism |
---|---|---|
malfunction | reduced APX activity, increased H2O2 level, and altered redox state of the ascorbate pool in mature pre-senescing green leaves of the apx6 mutants correlated with the early onset of senescence. Mutants of squamosa promoter binding protein-like7 (SPL7), the master regulator of copper homeostasis and miR398 expression, have a higher APX6 level compared to the wild-type, which further increases under copper deficiency. APX6-deficient mutants prematurely induce senescence programs triggered by the transition to flowering, extended darkness, and ethylene. Mutants of SPL7 show increased levels of APX6 in as yet flowering or senescing plants. The earlier onset of senescence in the mutants is accompanied by higher levels of H2O2 compared with the wild-type and reduced ability to adjust the leaves' redox state | Arabidopsis thaliana |
additional information | the coding sequence of APX6 is a potential target of miR398, which is a key regulator of copper redistribution | Arabidopsis thaliana |
physiological function | enzyme APX6 is a modulator of ROS/redox homeostasis and signaling in aging leaves that plays an important role in developmental- and stress-induced senescence programs. Senescence marks the last step in the development of annual plants, culminating in the death of tissues, and finally, the entire organism | Arabidopsis thaliana |