Dataset Information

Cytochromes P450 CYP94C1 and CYP94B3 catalyze two successive oxidation steps of plant hormone Jasmonoyl-isoleucine for catabolic turnover.

ABSTRACT: The jasmonate hormonal pathway regulates important defensive and developmental processes in plants. Jasmonoyl-isoleucine (JA-Ile) has been identified as a specific ligand binding the COI1-JAZ co-receptor to relieve repression of jasmonate responses. Two JA-Ile derivatives, 12OH-JA-Ile and 12COOH-JA-Ile, accumulate in wounded Arabidopsis leaves in a COI1- and JAR1-dependent manner and reflect catabolic turnover of the hormone. Here we report the biochemical and genetic characterization of two wound-inducible cytochromes P450, CYP94C1 and CYP94B3, that are involved in JA-Ile oxidation. Both enzymes expressed in yeast catalyze two successive oxidation steps of JA-Ile with distinct characteristics. CYP94B3 performed efficiently the initial hydroxylation of JA-Ile to 12OH-JA-Ile, with little conversion to 12COOH-JA-Ile, whereas CYP94C1 catalyzed preferentially carboxy-derivative formation. Metabolic analysis of loss- and gain-of-function plant lines were consistent with in vitro enzymatic properties. cyp94b3 mutants were largely impaired in 12OH-JA-Ile levels upon wounding and to a lesser extent in 12COOH-JA-Ile levels. In contrast, cyp94c1 plants showed wild-type 12OH-JA-Ile accumulation but lost about 60% 12COOH-JA-Ile. cyp94b3cyp94c1 double mutants hyperaccumulated JA-Ile with near abolition of 12COOH-JA-Ile. Distinct JA-Ile oxidation patterns in different plant genotypes were correlated with specific JA-responsive transcript profiles, indicating that JA-Ile oxidation status affects signaling. Interestingly, exaggerated JA-Ile levels were associated with JAZ repressor hyperinduction but did not enhance durably defense gene induction, revealing a novel negative feedback signaling loop. Finally, interfering with CYP94 gene expression affected root growth sensitivity to exogenous jasmonic acid. These results identify CYP94B3/C1-mediated oxidation as a major catabolic route for turning over the JA-Ile hormone.

SUBMITTER: Heitz T

PROVIDER: S-EPMC3307330 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cytochromes P450 CYP94C1 and CYP94B3 catalyze two successive oxidation steps of plant hormone Jasmonoyl-isoleucine for catabolic turnover.

Heitz Thierry T Widemann Emilie E Lugan Raphaël R Miesch Laurence L Ullmann Pascaline P Désaubry Laurent L Holder Emilie E Grausem Bernard B Kandel Sylvie S Miesch Michel M Werck-Reichhart Danièle D Pinot Franck F

The Journal of biological chemistry 20120103 9

The jasmonate hormonal pathway regulates important defensive and developmental processes in plants. Jasmonoyl-isoleucine (JA-Ile) has been identified as a specific ligand binding the COI1-JAZ co-receptor to relieve repression of jasmonate responses. Two JA-Ile derivatives, 12OH-JA-Ile and 12COOH-JA-Ile, accumulate in wounded Arabidopsis leaves in a COI1- and JAR1-dependent manner and reflect catabolic turnover of the hormone. Here we report the biochemical and genetic characterization of two wou ...[more]

PMID: 22215670

Similar Datasets

Project description:BackgroundJasmonate (JA) signaling and functions have been established in rice development and response to a range of biotic or abiotic stress conditions. However, information on the molecular actors and mechanisms underlying turnover of the bioactive jasmonoyl-isoleucine (JA-Ile) is very limited in this plant species.ResultsHere we explored two gene families in rice in which some members were described previously in Arabidopsis to encode enzymes metabolizing JA-Ile hormone, namely cytochrome P450 of the CYP94 subfamily (CYP94, 20 members) and amidohydrolases (AH, 9 members). The CYP94D subclade, of unknown function, was most represented in the rice genome with about 10 genes. We used phylogeny and gene expression analysis to narrow the study to candidate members that could mediate JA-Ile catabolism upon leaf wounding used as mimic of insect chewing or seedling exposure to salt, two stresses triggering jasmonate metabolism and signaling. Both treatments induced specific transcriptional changes, along with accumulation of JA-Ile and a complex array of oxidized jasmonate catabolites, with some of these responses being abolished in the JASMONATE RESISTANT 1 (jar1) mutant. However, upon response to salt, a lower dependence on JAR1 was evidenced. Dynamics of CYP94B5, CYP94C2, CYP94C4 and AH7 transcripts matched best the accumulation of JA-Ile catabolites. To gain direct insight into JA-Ile metabolizing activities, recombinant expression of some selected genes was undertaken in yeast and bacteria. CYP94B5 was demonstrated to catalyze C12-hydroxylation of JA-Ile, whereas similarly to its Arabidopsis bi-functional homolog IAR3, AH8 performed cleavage of JA-Ile and auxin-alanine conjugates.ConclusionsOur data shed light on two rice gene families encoding enzymes related to hormone homeostasis. Expression data along with JA profiling and functional analysis identifies likely actors of JA-Ile catabolism in rice seedlings. This knowledge will now enable to better understand the metabolic fate of JA-Ile and engineer optimized JA signaling under stress conditions.

Project description:Sunitinib is a multitargeted tyrosine kinase inhibitor associated with idiosyncratic hepatotoxicity. The mechanisms of this toxicity are unknown. We hypothesized that sunitinib undergoes metabolic activation to form chemically reactive, potentially toxic metabolites which may contribute to development of sunitinib-induced hepatotoxicity. The purpose of this study was to define the role of cytochrome P450 (P450) enzymes in sunitinib bioactivation. Metabolic incubations were performed using individual recombinant P450s, human liver microsomal fractions, and P450-selective chemical inhibitors. Glutathione (GSH) and dansylated GSH were used as trapping agents to detect reactive metabolite formation. Sunitinib metabolites were analyzed by liquid chromatography-tandem mass spectrometry. A putative quinoneimine-GSH conjugate (M5) of sunitinib was detected from trapping studies with GSH and dansyl-GSH in human liver microsomal incubations, and M5 was formed in an NADPH-dependent manner. Recombinant P450 1A2 generated the highest levels of defluorinated sunitinib (M3) and M5, with less formation by P450 3A4 and 2D6. P450 3A4 was the major enzyme forming the primary active metabolite N-desethylsunitinib (M1). In human liver microsomal incubations, P450 3A inhibitor ketoconazole reduced formation of M1 by 88%, while P450 1A2 inhibitor furafylline decreased generation of M5 by 62% compared to control levels. P450 2D6 and P450 3A inhibition also decreased M5 by 54 and 52%, respectively, compared to control. In kinetic assays, recombinant P450 1A2 showed greater efficiency for generation of M3 and M5 compared to that of P450 3A4 and 2D6. Moreover, M5 formation was 2.7-fold more efficient in human liver microsomal preparations from an individual donor with high P450 1A2 activity compared to a donor with low P450 1A2 activity. Collectively, these data suggest that P450 1A2 and 3A4 contribute to oxidative defluorination of sunitinib to generate a reactive, potentially toxic quinoneimine. Factors that alter P450 1A2 and 3A activity may affect patient risk for sunitinib toxicity.

Dataset Information

Cytochromes P450 CYP94C1 and CYP94B3 catalyze two successive oxidation steps of plant hormone Jasmonoyl-isoleucine for catabolic turnover.

Publications

Cytochromes P450 CYP94C1 and CYP94B3 catalyze two successive oxidation steps of plant hormone Jasmonoyl-isoleucine for catabolic turnover.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets