Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa

Guo, Liang; Fu, Chengjie; Miao, Wei

doi:10.1016/j.gene.2008.04.023

Cited by 18 publications

(19 citation statements)

References 33 publications

(66 reference statements)

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“…(74) Oxidative stress caused by H 2 O 2 or paraquat (PQ) induces MT gene expression, including both Tetrahymena Cd-and CuMTs. (11,29,30,31,33,38) However, other Tetrahymena CdMTs (TpyrMT-2) are not significantly induced by H 2 O 2 or PQ (TrosMTT1). (29,40) Starvation stress, mainly after 24 hour exposure, induces the gene expression of several Tetrahymena MT genes.…”

Section: Mt Gene Expression Multi-stress Response and Potential Regumentioning

confidence: 99%

“…(29,30,36,37) Both subfamilies differ in the induction patterns by heavy metals (Cd/Zn or Cu) and the pattern of Cys residue clustering. (29,30,31,34,37,38) The majority of Tetrahymena MT genes have been isolated as DNA complementary to RNA (cDNA) molecules, and from their alignment to the corresponding genomic DNA sequences, the absence of introns in all these MT genes has been revealed. On the other hand, introns have been described in several MTs from other organisms.…”

Section: Tetrahymena Mts Classificationmentioning

confidence: 99%

“…A similar hypothesis has been reported to explain the Tetrahymena MT evolution. (29,30,38,59) In Fig. 3, an updated model to explain the evolutionary history of Tetrahymena CdMTs is shown.…”

Section: Tetrahymena Mt Evolutionary Historymentioning

confidence: 99%

“…(67,68) Likewise, the Tetrahymena MT family presents a multistress response because its gene expression can be induced by very different stressors (including diverse heavy metals). (29,30,31,33,38) Comparisons of quantitative (q) realtime RT-PCR values obtained for Tetrahymena MT genes by various investigators is not easy due to differences in the experimental conditions and/or qRT-PCR protocols. (29,30,31,33,38) However, several general qualitative considerations may be inferred from the already published quantitative reverse transcription polymerase chain reaction (qRT-PCR) data (Table 3).…”

Section: Mt Gene Expression Multi-stress Response and Potential Regumentioning

confidence: 99%

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From heavy metal‐binders to biosensors: Ciliate metallothioneins discussed

2009

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Metallothioneins (MTs) are ubiquitous proteins with the capacity to bind heavy metal ions (mainly Cd, Zn or Cu), and they have been found in animals, plants, eukaryotic and prokaryotic micro-organisms. We have carried out a comparative analysis of ciliate MTs (Tetrahymena species) to well-known MTs from other organisms, discussing their exclusive features, such as the presence of aromatic amino acid residues and almost exclusive cysteine clusters (CCC) present in cadmium-binding metallothioneins (CdMTs), higher heavy metal-MT stoichiometry values, and a strictly conserved modular-submodular structure. Based on this last feature and an extensive gene duplication, we propose a possible model for the evolutionary history of T. thermophila MTs. We also suggest possible functions for these MTs from consideration of their differential gene expressions and discuss the potential use of these proteins and/or their gene promoters for designing molecular or whole-cell biosensors for a fast detection of heavy metals in diverse polluted ecosystems.

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Section: Mt Gene Expression Multi-stress Response and Potential Regumentioning

confidence: 99%

Section: Tetrahymena Mts Classificationmentioning

confidence: 99%

Section: Tetrahymena Mt Evolutionary Historymentioning

confidence: 99%

Section: Mt Gene Expression Multi-stress Response and Potential Regumentioning

confidence: 99%

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From heavy metal‐binders to biosensors: Ciliate metallothioneins discussed

2009

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“…Additional Tetrahymena MT sequences have since been reported: the MTT1, MTT2, MTT3, MTT4, and MTT5 genes of T. thermophila [Boldrin et al, 2002[Boldrin et al, , 2008Shang et al, 2002;Dondero et al, 2004;Santovito et al, 2007], the TpMT-2 gene of T. pyriformis [Fu and Miao, 2006], the MT-2 gene of T. pigmentosa [Boldrin et al, 2002] and TMCd1 gene of Tetrahymena tropicalis lahorensis [Shuja and Shakoori, 2007]. Recently, Guo et al [2008] have reported novel CdMT gene (Tpig-MTT1) in T. pigmentosa, while Amaro et al [2008] has reported isolation of two new MT genes (TrosMTT1 and TrosMTT2; Cd and Cu MT genes, respectively) from T. rostrata. Moreover, first cadmium metallothionein like gene (PMCdI) has also been isolated from Paramecium sp.…”

mentioning

confidence: 99%

Isolation and characterization of a novel copper‐inducible metallothionein gene of a ciliate, Tetrahymena tropicalis lahorensis

Chaudhry

Shakoori

2010

J of Cellular Biochemistry

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The two isoforms of copper metallothionein (CuMT) gene of a copper resistant ciliate, Tetrahymena tropicalis lahorensis (Ttl), have been isolated and characterized. The molecular cloning and nucleotide sequencing of cDNAs coding for the two CuMT isoforms revealed that TtlCuMT1 gene has 300, while TtlCuMT2 has 327 nucleotides, both with ATG as the initiation codon and TGA as the translational termination codon. TAG codes for glutamine in TtlCuMT2 gene which is peculiar to Tetrahymena. The deduced or translated TtlCuMT1 and TtlCuMT2 peptide sequences contain 100 and 108 amino acid residues including 28 and 32 cysteine residues, respectively. The amino acid sequences of TtlCuMT1 and TtlCuMT2 have special features of two and three CXCXXCXCXXCXC intragenic tandem repeats with a conserved structural pattern of cysteine, respectively. The predicted tertiary structures of these two isoforms indicate two domains. Domain I and the initial part of domain II showed >98% homology with other Tetrahymena CuMT. On the basis of the differences in the domain II, the metallothionein subfamily 7b can be divided into two groups, one (TtlCuMT1) comprising >100 amino acids and the other (TtlCuMT2) comprising <100 amino acids. This is a novel finding of the present study as no such report on this type of classification exists at the moment. TtlCuMT1 has 95%, while TtlCuMT2 has 97% resemblance with the previously reported CuMT genes of Tetrahymena spp. SDS-PAGE analysis using fluorescent probe as well as coomassie brilliant blue staining also confirmed the presence of metallothionein.

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Discrimination between two rice metallothionein isoforms belonging to type 1 and type 4 in metal‐binding ability

Nezhad

Shahpiri

Mirlohi

2013

Biotech and App Biochem

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Metallothioneins (MTs) are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. Plants have several MT isoforms, which are classified into four types based on the arrangement of Cys residues. In this study, two rice (Oryza sativa) MT isoforms, OsMTI-1b and OsMTII-1a from type 1 and type 4, respectively, were heterologously expressed in Escherichia coli as carboxy-terminal extensions of glutathione-S-transferase (GST). Transformed cells expressing GST-OsMTI-1b showed increased tolerance to Ni(2+) , Cd(2+) , and Zn(2+) and accumulated more metal ions compared with cells expressing GST alone. However, heterologous expression of GST-OsMTII-1a had no significant effects on metal tolerance or ion accumulation. The UV absorption spectra and competitive reactions of in vitro Cd-incubated proteins with 5-5'-dithiobis(2-nitrobenzoic) acid revealed that GST-OsMTI-1b, but not GST-OsMTII-1a, is able to form Cd-thiolate clusters. Furthermore, heterologous expression of both GST-OsMTI-1b and GST-OsMTII-1a conferred H2 O2 tolerance to E. coli cells. Taken together, the results presented here show that two different rice MT isoforms belonging to type 1 and type 4 differ in Ni(2+) , Cd(2+) , and Zn(2+) binding abilities, but they may have overlapping function in protection of cells against oxidative stress.

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Cloning, characterization, and gene expression analysis of a novel cadmium metallothionein gene in Tetrahymena pigmentosa

Cited by 18 publications

References 33 publications

From heavy metal‐binders to biosensors: Ciliate metallothioneins discussed

From heavy metal‐binders to biosensors: Ciliate metallothioneins discussed

Isolation and characterization of a novel copper‐inducible metallothionein gene of a ciliate, Tetrahymena tropicalis lahorensis

Discrimination between two rice metallothionein isoforms belonging to type 1 and type 4 in metal‐binding ability

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