Two genes encoding 1-aminocyclopropane-1-carboxylate synthase in zucchini (Cucurbita pepo) are clustered and similar but differentially regulated.

Huang, Pung‐Ling; Parks, Jean E.; Rottmann, William H.; Theologis, Athanasios

doi:10.1073/pnas.88.16.7021

Cited by 107 publications

(98 citation statements)

References 39 publications

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“…A single diffuse polyadenylated RNA of ~1.6 kb was apparent under both high and low hybridization stringency. This size corresponds to the size of the two full-length ACC synthase cDNA clones of orchid, ACC synthases 1 and 2 (OAS1 and OAS2, respectively), which we have characterized previously (A. Q. Bui and S. D. O'Neill, unpublished results; GenBank accession numbers L07882 for OAS1 and L07883 for OAS2), and with other ACC synthase mRNAs (Sato and Theologis, 1989;Nakajima et al, 1990;Van der Straeten et al, 1990;Huang et al, 1991;Nakagawa et al, 1991;Olson et al, 1991;Sato et al, 1991;Dong et al, 1992;Park et al, 1992 ACC synthase mRNA (AS) abundance was analyzed using OAS1 cDNA to probe RNA gel blots, and ACC oxidase (AO) mRNA abundance was analyzed using an OAO1 cDNA probe. Each lane contains 2.5 ng of poly(A) + RNA (gynoecium) or 5.0 ng of poly(A) + RNA (labellum and perianth).…”

Section: Genes Encoding Ethylene Biosynthetic Enzymes Are Regulated Bmentioning

confidence: 99%

Interorgan regulation of ethylene biosynthetic genes by pollination.

et al. 1993

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Pollination initiates a syndrome of developmental events that contribute to successful reproduction, including perianth senescence, changes in pigmentation, and ovule differentiation in preparation for impending fertilization. In orchid flowers, initiation of each of these processes in distinct floral organs is strictly and coordinately controlled by pollination, thus providing a unique opportunity to study the signals that coordinate interorgan postpollination development. Because ethylene has been implicated in contributing to regulation of severa1 aspects of postpollination development, we focused on determining the expression of its biosynthetic genes and their possible role in regulation. The abundance of mRNA encoding both 1-aminocyclopropane-l-carboxylic acid (ACC) synthase and ACC oxidase in the stigma, ovary, and labellum was found to be coordinately regulated by emasculation, auxin, and ethylene. Although petals contribute up to 26% of total flower ethylene and accumulate high levels of ACC oxidase mRNA and activity following pollination, no ACC synthase mRNA or activity was detected in this tissue. Together, these results support a model of interorgan regulation of postpollination development that depends on pollination-stimulated accumulation of mRNA encoding ethylene biosynthetic enzymes in a developmentally regulated and tissue-specific manner. This model relies on the translocation of a soluble hormone precursor, ACC, rather than on the translocation of the hormone itself. In this way, ACC serves to actuate the response already initiated by ethylene perceived by other parts of the flower. Thus, ACC may function as a secondary transmissible signal that coordinates postpollination development in diverse floral organs.

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Section: Genes Encoding Ethylene Biosynthetic Enzymes Are Regulated Bmentioning

confidence: 99%

Interorgan regulation of ethylene biosynthetic genes by pollination.

et al. 1993

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“…Moreover, the LlACS sequence contains 11 amino acids characteristic for ACSs and various aminotransferases (Fig. S1d) [18,19]. The fulllength of LlACO cDNA encoded 317 amino acids (Fig.…”

Section: Isolation Of Llacs and Llaco Cdnasmentioning

confidence: 99%

Ethylene-dependent effects on generative organ abscission of Lupinus luteus

et al. 2017

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The abscission of certain organs from the plant is part of the fulfilment of its developmental programs. The separation process occurs in a specialized abscission zone usually formed at the base of detached organ. The changing level of phytohormones, particularly ethylene, is the element responsible for coordinating anatomical and physiological transformation that accompanies organ abscission. The application of ethylene (ET) on Lupinus luteus stimulates flower abortion. However, the treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) -direct ET precursor -does not cause such a strong physiological response. In turn, when applied on the pedicels both ET biosynthesis (2-aminoethoxyvinylglycine; AVG) and action (norbornadiene; NBD) inhibitors reversed the stimulatory effect of ET on generative organ separation. In order to determine ET role in the flower abscission process in L. luteus, we identified the sequences coding for synthase (LlACS) and oxidase (LlACO) of ACC and measured their expression levels. Abscission zone activation is accompanied by a considerable increase both in LlACS and LlACO cDNAs and also ACC content, which is specifically localized in the dividing cells at the base of the flower being detached. Obtained results suggest that ET is a strong stimulator of flower abortion in L. luteus.

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“…1I). The homology between ACS and aminotransferases such as AspAT suggests that these two groups of enzymes may be evolutionary related and raises the possibility that the quaternary structure and co-factor binding sites of these two groups of enzymes may be similar (4,5).…”

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confidence: 99%

“…ACS is a pyridoxal phosphate (PLP)-dependent enzyme that is proposed to undergo an ␣,␥-1,3 elimination reaction that is unique among all PLP-dependent enzymes (2,3). ACS also shares sequence similarity with another group of PLP-dependent enzymes, the aminotransferases (4,5). A recent alignment indicates that ACSs have the highest similarity to a sub-group of aminotransferases that includes alanine-, tyrosine-, histidinol phosphate-, phenylalanine-, and aspartate (AspAT) aminotransferases and share all the 11 invariant residues in this subgroup including four conserved residues (Gly-197, Asp-222, Lys-258, Arg-386) present in all aminotransferases (Ref.…”

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confidence: 99%

Complementation Analysis of Mutants of 1-Aminocyclopropane1-carboxylate Synthase Reveals the Enzyme Is a Dimer with Shared Active Sites

Tarun

Theologis

1998

Journal of Biological Chemistry

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The pyridoxal phosphate-dependent enzyme 1-aminocyclopropane-1-carboxylate synthase (ACS, EC 4.4.1.14) catalyzes the rate-limiting step in the ethylene biosynthetic pathway. ACS shares the conservation of 11 invariant residues with a family of aminotransferases that includes aspartate aminotransferase. Site-directed mutagenesis on two of these residues, Tyr-92 and Lys-278, in the tomato isoenzyme Le-ACS2 greatly reduces enzymatic activity, indicating their importance in catalysis. These mutants have been used in complementation experiments either in vivo in Escherichia coli or in an in vitro transcription/translation assay to study whether the enzyme functions as a dimer. When the Y92L mutant is coexpressed with the K278A mutant protein, there is partial restoration of enzyme activity, suggesting that the mutant proteins can dimerize and form active heterodimers. Coexpressing a double mutant with the wildtype protein reduces wild-type activity, indicating that inactive heterodimers are formed between the wild-type and the double mutant protein subunits. Furthermore, hybrid complementation shows that another tomato isoenzyme, Le-ACS4, can dimerize and that Le-ACS2 and Le-ACS4 have limited capacity for heterodimerization. The data suggest that ACS functions as a dimer with shared active sites.Ethylene is an endogenous plant hormone that regulates many aspects of plant growth and development (1). The ratelimiting step in ethylene biosynthesis is the conversion of Sadenosylmethionine to the cyclic amino acid 1-aminocyclopropane-1-carboxylic acid (ACC) 1 and methylthioadenosine catalyzed by the enzyme S-adenosyl-L-methionine methylthioadenosine-lyase (ACS, EC 4.4.1.14). ACS is a pyridoxal phosphate (PLP)-dependent enzyme that is proposed to undergo an ␣,␥-1,3 elimination reaction that is unique among all PLP-dependent enzymes (2, 3). ACS also shares sequence similarity with another group of PLP-dependent enzymes, the aminotransferases (4, 5). A recent alignment indicates that ACSs have the highest similarity to a sub-group of aminotransferases that includes alanine-, tyrosine-, histidinol phosphate-, phenylalanine-, and aspartate (AspAT) aminotransferases and share all the 11 invariant residues in this subgroup including four conserved residues (Gly-197, Asp-222, Lys-258, Arg-386) present in all aminotransferases (Ref. 6, see Fig. 1I). The homology between ACS and aminotransferases such as AspAT suggests that these two groups of enzymes may be evolutionary related and raises the possibility that the quaternary structure and co-factor binding sites of these two groups of enzymes may be similar (4, 5).The subunit structure of ACS is unresolved. Although most published reports indicate that the enzyme is a homodimer (7-10), experimental evidence suggests that ACS purified from tomato (7, 11) and apple fruits (12) are monomers. AspAT is a homodimer with functionally independent active sites formed by the interaction of residues from both subunits and thus cannot function as a monomer (13). It is possible that ACS may als...

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Two genes encoding 1-aminocyclopropane-1-carboxylate synthase in zucchini (Cucurbita pepo) are clustered and similar but differentially regulated.

Cited by 107 publications

References 39 publications

Interorgan regulation of ethylene biosynthetic genes by pollination.

Interorgan regulation of ethylene biosynthetic genes by pollination.

Ethylene-dependent effects on generative organ abscission of Lupinus luteus

Complementation Analysis of Mutants of 1-Aminocyclopropane1-carboxylate Synthase Reveals the Enzyme Is a Dimer with Shared Active Sites

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