Characterization of the cis-acting element directing perinuclear localization of the metallothionein-1 mRNA

• Published in: Biochemical Society transactions Vol. 32; no. Pt 5; p. 702
• Main Authors: Chabanon, H, Nury, D, Mickleburgh, I, Burtle, B, Hesketh, J
• Format: Journal Article
• Language: English
• Published: England 01.11.2004
• Subjects: 3' Untranslated Regions; Actins - genetics; Animals; Base Sequence; Cell Nucleus - metabolism; Cricetinae; Cross-Linking Reagents - pharmacology; Cytoplasm - metabolism; Cytoskeleton - metabolism; Humans; Metallothionein - biosynthesis; Metallothionein - genetics; Mice; Molecular Sequence Data; Mutation; Polyribosomes - chemistry; Protein Structure, Secondary; Response Elements; RNA, Messenger - chemistry; RNA, Messenger - metabolism; Sequence Homology, Nucleic Acid; Ultraviolet Rays
• ISSN: 0300-5127
• DOI: 10.1042/BST0320702

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.