Subcellular localization of mRNAs is a key mechanism for the synthesis of proteins close to their site of function. The mRNA encoding MT-1 (metallothionein-1) is localized in the perinuclear cytoplasm, where it is associated with cytoskeletal-bound polysomes. This localization relies on sequences present in the 3′-UTR (3′-untranslated region). The present study aims to characterize the cis-acting localization element(s) within the 3′-UTR. Using transfected cells expressing tagged MT-1 differing in their 3′-UTRs (deleted or mutated), the section(s) of this region required for directing MT-1 transcripts to the perinuclear cytoplasm has been investigated. Different 3′-UTRs were also used in UV cross-linking experiments that highlighted two distinct regions (nt 26–30 and 66–76) necessary for the binding of a protein of approx. 50 kDa, presumably involved in the mRNA targeting. The poor sequence homology between the MT-1 3′-UTR of various species, together with the bipartite nature of the required cis-element, indicates the involvement of a particular structure in the localization signal. The secondary structure of the MT-1 3′-UTR was investigated using enzymic and chemical probing. Current structural analysis of mutant 3′-UTRs will allow the critical structural features of the MT-1 mRNA perinuclear localization signal to be defined.
Characterization of the cis-acting element directing perinuclear localization of the metallothionein-1 mRNA
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H. Chabanon, D. Nury, I. Mickleburgh, B. Burtle, J. Hesketh; Characterization of the cis-acting element directing perinuclear localization of the metallothionein-1 mRNA. Biochem Soc Trans 1 November 2004; 32 (5): 702–704. doi: https://doi.org/10.1042/BST0320702
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