Gene expression metal-regulated

MT gene expression is largely regulated at the transcriptional level. Enhanced MT expression may also be attributed to MT gene amplification. However, the specific mechanism by which MT gene expression is regulated in vivo in response to metal exposure is as yet unclear. In addition to metals, a number of other stimuli are known to induce MT, namely glucocorticoids, cytokines, oxidative stress, and a variety of chemicals. 

Zinc (Zn +) is the second most abundant metal ion after iron in the human body, and plays critical roles in regulating gene expression, enzyme regulation, and neurotransmission [90]. Zn + is also known to be responsible for the formation of amyloid plaques during the onset of Alzheimer s disease [91], At present, there is considerable interest in the development of Zn +-selective luminescence chemosensors as bioimaging probes [92, 93],... 

Metal-binding proteins and metal-regulated gene expression in higher plants... 

In this chapter we examine the relationship between metal homeostasis (i.e. essential metal metabolism and protection from metal toxicity) and metal tolerance, and the role that metal-binding proteins and metal-regulated gene expression play in these processes. 

Cellular responses to metal ions include changes of patterns of gene expression. Many of these changes are non-specific shock effects for example, subsets of the heat shock proteins are synthesised in response to Cd (Czarnecka et al., 1984 Lin et al., 1984 Delhaize et al., 1989). However, some mRNAs are specifically induced by Cd (Delhaize et al., 1989). Thus, by examining metal-regulated gene expression, whether specific or non-specific, it may be possible to determine the relative roles of proteins and polypeptides specific to metal homeostasis and metal tolerance, as opposed to functions involved in general stress responses. 

Several systems have been established which can regulate gene expression. For instance, there are systems which rely on the addition of steroid hormones or heavy metal ions. However, certain physiologic or toxic effects may result and high basal-transcriptional activity may limit their usefulness (Furth et al., 1994). Another approach has been developed which is based on the tetracycline-resistance operon tet from E. coli transposon Tn70. 

Andrews, G.K. (2000) Regulation of metallothionein gene expression by oxidative stress and metal ions. Biochem. Pharmacol., 59, 95-104. 

Heuchel, R., Radtke, F. and Schaffner, W. (1995) Transcriptional regulation by heavy metals, exemplified at the metallothionein genes. In P A.Baeuerle (ed.) Inducible Gene Expression, Vol. I, Birkhauser, Boston. 

The role of metals, and in particular Zn, in the regulation of gene expression has been a subject of recent studies in the last decade. The term zinc finger for this type of structure is generally accepted [8,9], The Zn(II) ion does not act as a catalyst, but resembles more a cofactor that folds the protein in a specific conformation, as a result of which it binds to nucleic acids, such that certain genes are being activated for expression [9],... 

The expression of HMPAs is commonly controlled by their ligands, heavy metals, which may interact with a regulatory element(s) up- or down-regulating their gene expression (Rensing et al., 2000). Also, in... 

Zawia NH, Sharan R, Brydie M, Oyama T, Crumpton T (1998) Spl as a target site for metal-induced perturbation of transcriptional regulation of developmental biain gene expression. Dev Brain Res 107 291-298... 

Non-wood plants will sometimes grow extremely large at certain sites of high humidity and plentiful trace element availability from volcano soils (Ruwenzori Mountains, Azores Islands), suggesting an influence of trace metals which are more abundant there on gene expression and thus growth regulation. 

Winge DR, Jensen LT, Srinivasan C. Metal-ion regulation of gene expression in yeast. Curr. Opin. Chem. Biol. 1998 2 216—221. 

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