Biochemical characterization of the maize cytokinin dehydrogenase family and cytokinin profiling in developing maize plantlets in relation to the expression of cytokinin dehydrogenase genes
Jazyk angličtina Země Francie Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
24333683
DOI
10.1016/j.plaphy.2013.11.020
PII: S0981-9428(13)00415-4
Knihovny.cz E-zdroje
- Klíčová slova
- 2,6-dichlorophenolindophenol, AtCKX, CKX, Cytokinin, Cytokinin dehydrogenase, DCPIP, DHZ, DMAPP, EDTA, Escherichia coli IMPACT expression system, IPT, N(6)-(Δ(2)-isopentenyl)adenine, N(6)-(Δ(2)-isopentenyl)adenine-N9-glucoside, N(6)-(Δ(2)-isopentenyl)adenosine, N(6)-(Δ(2)-isopentenyl)adenosine-5′-monophosphate, Substrate preference, Zea mays L., ZmCKX, cZ, cZ9G, cZRMP, cis-zeatin, cis-zeatin riboside-5′-monophosphate, cis-zeatin-N9-glucoside, cytokinin dehydrogenase, cytokinin dehydrogenase from Arabidopsis thaliana, cytokinin dehydrogenase from Zea mays, dihydrozeatin, dimethylallyl diphosphate, ethylenediaminetetraacetic acid, iP, iP9G, iPR, iPRMP, isopentenyl transferase, tZ, tZ9G, tZR, tZRMP, trans-zeatin, trans-zeatin riboside, trans-zeatin riboside-5′-monophosphate, trans-zeatin-N9-glucoside,
- MeSH
- chromatografie afinitní MeSH
- chromatografie iontoměničová MeSH
- cytokininy metabolismus MeSH
- DNA primery MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- fylogeneze MeSH
- kukuřice setá enzymologie růst a vývoj metabolismus MeSH
- molekulární sekvence - údaje MeSH
- mutageneze cílená MeSH
- oxidoreduktasy chemie genetika metabolismus MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- regulace genové exprese enzymů * MeSH
- regulace genové exprese u rostlin * MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- substrátová specifita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokinin oxidase MeSH Prohlížeč
- cytokininy MeSH
- DNA primery MeSH
- oxidoreduktasy MeSH
The cytokinin dehydrogenases (CKX; EC 1.5.99.12) are a protein family that maintains the endogenous levels of cytokinins in plants by catalyzing their oxidative degradation. The CKX family in maize (Zea mays L.) has thirteen members, only two of which--ZmCKX1 and ZmCKX10--have previously been characterized in detail. In this study, nine further maize CKX isoforms were heterologously expressed in Escherichia coli, purified by affinity and ion-exchange chromatography and biochemically characterized. ZmCKX6 and ZmCKX9 could only be expressed successfully after the removal of putative sequence-specific vacuolar sorting signals (LLPT and LPTS, respectively), suggesting that these proteins are localized to the vacuole. Substrate specificity analyses revealed that the CKX isoforms can be grouped into two subfamilies: members of the first strongly prefer cytokinin free bases while members of the second degrade a broad range of substrates. The most active isoform was found to be ZmCKX1. One of the studied isoforms, ZmCKX6, seemed to encode a nonfunctional enzyme due to a mutation in a conserved HFG protein domain at the C-terminus. Site-directed mutagenesis experiments revealed that this domain is essential for CKX activity. The roles of the maize CKX enzymes in the development of maize seedlings during the two weeks immediately after radicle emergence were also investigated. It appears that ZmCKX1 is a key regulator of active cytokinin levels in developing maize roots. However, the expression of individual CKX isoforms in the shoots varied and none of them seemed to have strong effects on the cytokinin pool.
Citace poskytuje Crossref.org
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