Gene transcriptions/Elements/Metal responsives

Metal responsive elements (MRE)s, or TGC boxes, may occur in the core promoter of some human DNA genes.

TGC boxes


Notation: let the symbol MT stand for metallothionein.

"The metallothionein (MT) genes provide a good example of eucaryotic promoter architecture. MT genes specify the synthesis of low-molecular-weight metal-binding proteins. They are transcriptionally regulated by the metal ions cadmium and zinc (11), glucocorticoid hormones (18), interferon (14), interleukin-1 (22), and tumor promoters (2). The metal ion regulation of MTs is conferred by a short sequence element called the metal-responsive element (MRE [21]) or TGC box (31, 34), which functions as a metal ion-dependent enhancer."[1]

Consensus sequences


"The promoter regulatory sequences are identified by homology to published GRE (21), MRE (35), and GC box (15) consensus sequences."[1]

Here "is a consensus sequence for the MREs of the rat MT-1 gene."[1] In the direction of transcription on the DNA template strand: 3'-CNNTGCRCYCGGGNC-5', where R = purine; Y = pyrimidine; and N = any nucleotide (nt).[1]

"[T]hree potential metal response elements (MREs) [overlap] the E-boxes in the repeats, (TGCACGT with TGCRCNC being the consensus sequence; 17,18)."[2]

The reproducible consensus sequence seems to be 3'-TGCRCNC-5', specifically 3'-TGC(A/G)CNC-5'.



Six MREs lie in the proximal promoter of the rat MT-1 gene upstream of the TATA box to almost -200 nts from the transcription start site.[1]


  1. At least two human gene isoforms have their transcription initiated by an MRE.

See also



  1. 1.0 1.1 1.2 1.3 1.4 Robert D. Andersen, Susan J. Taplitz, Sandy Wong, Greg Bristol, Bill Larkin, and Harvey R. Herschman (October 1987). "Metal-Dependent Binding of a Factor In Vivo to the Metal-Responsive Elements of the Metallothionein 1 Gene Promoter". Molecular and Cellular Biology 7 (10): 3574-81. doi:10.1128/​MCB.7.10.3574. Retrieved 2013-04-15. 
  2. Barbara Levinson, Rebecca Conant, Rhonda Schnur, Soma Das, Seymour Packman and Jane Gitschier (1996). "A Repeated Element in the Regulatory Region of the MNK Gene and Its Deletion in A Patient With Occipital Horn Syndrome". Human Molecular Genetics 5 (11): 1737-42. doi:10.1093/hmg/5.11.1737. Retrieved 2013-04-15. 

Further reading