Expression of the type 2 metallothionein-like gene MT2 from Arabidopsis thaliana in Zn2+-metallothionein-deficient Synechococcus PCC 7942: putative role for MT2 in Zn2+ metabolism

Robinson, Nigel J.; Wilson, J.; Turner, Jennifer S.

doi:10.1007/bf00019550

Cited by 58 publications

(25 citation statements)

References 46 publications

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“…In addition to ricMT, many MT-like protein genes have been found in plants (Buchanan-Wollaston 1994;Choi et al 1996;Coupe et al 1995;Foley and Singh 1994;Hsieh et al 1995;Hudspeth et al 1996;Robinson et al 1996;Snowden et al 1995;Zhou and Goldsbrough 1995). Considerable data are available on their structure and expression, and such data have enhanced our understanding of their roles in plant metabolism.…”

Section: Expression Pattern Of Gus Gene In Transgenic Plantsmentioning

confidence: 96%

The rice metallothionein gene promoter does not direct foreign gene expression in seed endosperm

Fukuzawa

Umeda-Hara

et al. 2004

Plant Cell Rep

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We generated transgenic tobacco and rice plants harboring a chimeric gene consisting of the 5'-upstream sequence of the rice metallothionein gene (ricMT) fused to the beta-glucuronidase (GUS) gene. The activity and tissue-specific expression of the ricMT promoter were demonstrated in these transgenic plants. In the transgenic rice plants, despite substantial levels of GUS activity in the shoot and root, almost no GUS signal was detected in the endosperm. Thus, the ricMT promoter could be useful in avoiding accumulation of undesired proteins in the seed endosperm.

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Section: Expression Pattern Of Gus Gene In Transgenic Plantsmentioning

confidence: 96%

The rice metallothionein gene promoter does not direct foreign gene expression in seed endosperm

Fukuzawa

Umeda-Hara

et al. 2004

Plant Cell Rep

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“…MTs are known to participate in Cu homeostasis (Cobbett and Goldsbrough 2002) and A. thaliana MT1 and MT2 complement the S. cerevisiae MT-defective cup1 mutant and confer Cd tolerance (Zhou and Goldsbrough 1994). A. thaliana MT2 can also partially rescue the Zn hypersensitivity of a Synechococcus amtA mutant, which is deficient for an endogenous Zn 2+ -MT gene (Robinson et al 1996). The expression pea MT type I as a GSH transferase fusion in E. coli increases Cu accumulation (Evans et al 1992), and the expression of B. juncea MT2 in A. thaliana enhances Cd and Cu tolerance (Zhigang et al 2006).…”

Section: Metallothioneins and Ferritinsmentioning

confidence: 98%

Plant Responses to Heavy Metal Toxicity

Manara

2012

SpringerBriefs in Molecular Science

188

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Plants, like all other organisms, have evolved different mechanisms to maintain physiological concentrations of essential metal ions and to minimize exposure to non-essential heavy metals. Some mechanisms are ubiquitous because they are also required for general metal homeostasis, and they minimize the damage caused by high concentrations of heavy metals in plants by detoxification, thereby conferring tolerance to heavy metal stress. Other mechanisms target individual metal ions (indeed some plants have more than one mechanism to prevent the accumulation of specific metals) and these processes may involve the exclusion of particular metals from the intracellular environment or the sequestration of toxic ions within compartments to isolate them from sensitive cellular components. As a first line of defense, many plants exposed to toxic concentrations of metal ions attempt to prevent or reduce uptake into root cells by restricting metal ions to the apoplast, binding them to the cell wall or to cellular exudates, or by inhibiting long distance transport. If this fails, metals already in the cell are addressed using a range of storage and detoxification strategies, including metal transport, chelation, trafficking, and sequestration into the vacuole. When these options are exhausted, plants activate oxidative stress defense mechanisms and the synthesis of stress-related proteins and signaling molecules, such as heat shock proteins, hormones, and reactive oxygen species.

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“…In contrast to identification of several mt-like genes in plants, there are few studies on purified proteins. Apart from Ec and Arabidopsis thaliana MTs (23), only the pea type 1 MT (PsMT A ) was expressed in Escherichia coli to characterize the protein and determine its metal-binding properties (24,25).…”

Section: Metallothioneins (Mts)mentioning

confidence: 99%

Triticum durum Metallothionein

Bilecen

Ozturk

Duru

et al. 2005

Journal of Biological Chemistry

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A novel gene sequence, with two exons and one intron, encoding a metallothionein (MT) has been identified in durum wheat Triticum durum cv. Balcali85 genomic DNA. Multiple alignment analyses on the cDNA and the translated protein sequences showed that T. durum MT (dMT) can be classified as a type 1 MT. dMT has three Cys-X-Cys motifs in each of the Nand C-terminal domains and a 42-residue-long hinge region devoid of cysteines. dMT was overexpressed in Escherichia coli as a fusion protein (GSTdMT), and bacteria expressing the fusion protein showed increased tolerance to cadmium in the growth medium compared with controls. Purified GSTdMT was characterized by SDS-and native-PAGE, size exclusion chromatography, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. It was shown that the recombinant protein binds 4 ؎ 1 mol of cadmium/mol of protein and has a high tendency to form stable oligomeric structures. The structure of GSTdMT and dMT was investigated by synchrotron x-ray solution scattering and computational methods. X-ray scattering measurements indicated a strong tendency for GSTdMT to form dimers and trimers in solution and yielded structural models that were compatible with a stable dimeric form in which dMT had an extended conformation. Results of homology modeling and ab initio solution scattering approaches produced an elongated dMT structure with a long central hinge region. The predicted model and those obtained from x-ray scattering are in agreement and suggest that dMT may be involved in functions other than metal detoxification. Metallothioneins (MTs)1 constitute a superfamily of ubiquitously expressed low molecular mass (6 -7 kDa), cysteine-rich proteins lacking aromatic amino acids (1). After first being identified as a cadmium-binding protein in horse kidney (2), MTs were found in a wide range of organisms from plants to fungi, and their high capacity to bind metals (e.g. copper, cadmium, zinc, mercury, and silver) in metal-thiolate clusters was demonstrated (3, 4). Several functional roles have been attributed to MTs, including heavy metal detoxification, zinc and copper homeostasis (5, 6), scavenging of reactive oxygen species (7), regulation of metalloenzymes and transcription factors (5), involvement in metabolism of metallo-drugs and alkylating agents, response to stress conditions, and the potential involvement at inflammatory sites and in apoptosis (8).Historically, MTs have been classified in three groups according to their sequence similarities. Class I consists of those with high sequence homology to mammalian MTs; class II includes all that do not display significant similarity to class I, and class III consists of phytochelatins, enzymatically synthesized peptides with a poly(␥-glutamylcysteinyl)glycine structure found in plants (9). In recent years computational analyses resulted in a more detailed classification, where the MT superfamily was divided into families, classes, and subclasses based on the location and distribution of the cysteine residues (10)...

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Expression of the type 2 metallothionein-like gene MT2 from Arabidopsis thaliana in Zn2+-metallothionein-deficient Synechococcus PCC 7942: putative role for MT2 in Zn2+ metabolism

Cited by 58 publications

References 46 publications

The rice metallothionein gene promoter does not direct foreign gene expression in seed endosperm

The rice metallothionein gene promoter does not direct foreign gene expression in seed endosperm

Plant Responses to Heavy Metal Toxicity

Triticum durum Metallothionein

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