| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1316992 | Journal of Inorganic Biochemistry | 2011 | 10 Pages |
Metallothioneins (MTs) are a superfamily of Cys-rich polypeptides that bind heavy metal ions, both for physiological and detoxification purposes. They are present in all organisms, but their origin is probably polyphyletic, so that MT evolutionary studies are rather scarce. We present a thorough search and analysis of the MT coding sequences in the 12 Drosophila genomes completely sequenced, taking as reference the features reported for D. melanogaster, where four isogenes (MtnA to MtnD) are known and deeply characterized. We include a fifth isoform in this study, named MtnE, and recently annotated. The MTs polymorphism pattern is essentially the same for the 12 Drosophila species. Invariably, a MtnA form and an MtnB-cluster, comprising the MtnB-to-MtnE forms in tandem array, are observed. The whole set of genes are kept in the same synteny element (Muller E), but implicated in rearrangement events (mainly inversions), encompassing all or some of the isogenes. Gene exon/intron architecture, and cDNA and protein sequences appear highly conserved through Drosophila speciation, concordantly with an essential function for MT isoforms in flies, even for those previously considered as minor products. Data presented here will be comprehensively analyzed to provide a valuable guide for future MT evolutionary, structure and function studies.
Graphical abstractThe in silico analysis of the Drosophila metallothionein (MT) subfamily, with its nearly 60 isoforms, including paralogous and orthologous sets of genes and proteins, provides an excellent system for MT evolution, differentiation and function studies.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 5 paralogs MT genes are present in each of the 12 annotated Drosophila genomes. ► Expansion of the MT family is older than the Drosophila genus speciation. ► Chromosomal localization, gene architecture and sequence are highly conserved. ► Most amino acid changes are determinants of taxonomic groups. ► The supposed secondary isoform, MtnD shows the highest degree of conservation.
