Disease relevance of MT2A

• The turkey metallothionein gene (tkMT) was isolated from a phage lambda-turkey genomic DNA library by virtue of high identity with chicken MT cDNA [1].
• Lipopolysaccharide-injected birds developed heavier livers, spleens and intestines relative to body weights and higher rectal temperatures and hepatic metallothionein concentrations, presumably due to an immunologic stress [2].
• Pre-treatment of chondrocytes with dexamethasone resulted in suppressed synthesis of MT upon Cd exposure and greater Cd toxicity [3].
• Collectively, the changes in serum zinc, copper, and iron concentrations, as well as the changes in hepatic zinc and MT-zinc concentrations in the chicks infected with E. tenella were similar to changes evoked during an acute phase response to infection [4].

High impact information on MT2A

• The complete amino acid sequence of metallothionein (MT) from chicken liver is reported [5].
• In the chicken liver, levels of chicken MT mRNA were rapidly induced by metals (Cd2+, Zn2+, Cu2+), glucocorticoids and lipopolysaccharide [6].
• The nucleotide sequence of the coding region of chicken MT shares approximately 70% homology with the consensus sequence for the mammalian MTs [6].
• Pre-treatment of 14-day embryos with chromium(VI) inhibited the zinc(II)-induced increase in steady-state levels of metallothionein mRNA and protein in liver by 30-50% [7].
• Metallothionein expression varied with the stage of embryo development, with basal steady-state mRNA levels being approximately three times lower in livers of 18-day versus 14-day chicken embryos [7].

Chemical compound and disease context of MT2A

• Supplementation of culture media with cysteine and/or methionine resulted in higher levels of MT induction and reduced toxicity during Cd exposure [8].

Biological context of MT2A

• Amino acid sequence and comparative antigenicity of chicken metallothionein [5].
• The chicken metallothionein (MT) cDNA and gene were cloned, and their nucleotide sequences determined [9].
• The placement of the intervening sequences in the chicken gene is nearly identical with that in the mammalian MT genes [9].
• The chicken MT gene is structurally homologous with the mammalian MT genes; consisting of three exons separated by two intervening sequences [9].
• We conclude that different antibiotics increase the accumulation of hepatocyte MT mRNA by different mechanisms and that the possibility of multiple mechanisms should be considered in other studies of the role of protein synthesis in gene expression [10].

Anatomical context of MT2A

• Removal of Cd2+ from medium previously containing 20 microM-Cd2+ also decreased the absolute rate of MT accretion in macrophages [11].
• The ontogeny and induction by zinc of hepatic chick embryo metallothionein [12].
• Both 109Cd radioassay analysis and gel filtration chromatography of hepatic cytosols showed a developmental pattern for MT similar to that of cytosolic Zn [12].
• 109Cd radioassay analysis of liver (L), kidney (K) and pancreas (P) showed a significant elevation of MT in all tissues except K of i.v. chicks [13].
• Monocyte metallothionein mRNA levels were significantly greater than those of controls by d 2 of supplementation [14].

Associations of MT2A with chemical compounds

• MT mRNA was present in low levels in embryonic liver, but was inducible in ovo by injection of metal ions, glucocorticoids or LPS [9].
• Estimates of the half-life of MT mRNA by using actinomycin D suggested for cycloheximide, but not puromycin, decreased the decay rate of MT mRNA [10].
• Incubation with puromycin or zinc for 2 h markedly increased the rate of MT gene transcription [10].
• Nuclear run-off assays showed only a slight (1.5-fold) increase in calbindin-D28K gene transcription 2 h after 1,25-(OH)2D3, whereas parallel assays clearly demonstrated a marked (7-fold) induction in the rate of metallothionein gene transcription 2 h after treatment of chick kidney cells with 10 microM zinc [15].
• Zinc and cadmium, both of which bind to metallothionein, are most widely recognized as potent inducers [16].

Other interactions of MT2A

• Increasing the concentration of dietary fish oil decreased febrile response, circulating hemopexin and metallothionein concentrations [17].

Analytical, diagnostic and therapeutic context of MT2A

• The comparative antigenicity of chicken MT was determined by radioimmunoassay using rabbit anti-rat MT polyclonal antibody [5].
• Southern blot analyses of total genomic DNA, and cloned chicken DNA indicated that the MT gene is a unique gene sequence [9].
• Molecular cloning of chicken metallothionein. Deduction of the complete amino acid sequence and analysis of expression using cloned cDNA [6].
• In order to further explore the degree of conservation of the protein coding regions of avian MT genes, partial MT cDNAs from turkey, quail (qMT), and pheasant (pMT) were amplified using the reverse transcriptase-polymerase chain reaction (RT-PCR) and primers corresponding to the amino- and carboxyl-terminal coding regions of cMT mRNA [1].
• Iron administered to chicks by intravenous or subcutaneous injection caused a 1.9-fold increase in hepatic MT [18].

References