Two separate and evolutionarily divergent duplication events from an Lixisenatide solubility ancestral XOR
Two separate and evolutionarily divergent duplication events from an ancestral XOR gene. The first event produced the aldehyde oxidase precursor to worm,insect and plant enzymes. The second led to the appearance of the vertebrate counterpart. This is supported by the intron/exon structure of all the vertebrate aldehyde oxidase and XOR genes, which are strikingly conserved and much more complex than those of homologues from the lower eukaryotes and plants.1,8 The two original duplications were followed by a number of other such events that led to the extant complement of aldehyde oxidase genes in the plant and animal kingdoms.# HENRY STEWART PUBLICATIONS 1479 ?364. HUMAN GENOMICS. VOL 4. NO. 2. 119 ?30 DECEMBERThe mammalian aldehyde oxidase gene familyUPDATE ON GENE COMPLETIONS AND ANNOTATIONSFigure 1. Phylogeny of eukaryotic aldehyde oxidases. A rooted dendrogram was obtained by the Phylip method after CLUSTAL-W computer-aided alignment of the indicated proteins. Poere AOX1 ?Poecilia reticulata (guppy) AOX1; Coeel AOX1/AOX2 ?Caenorhabditis elegans AOX1 and AOX2; Drome AOX1/AOX2/AOX3/AOX4 ?Drosophila melanogaster AOX1, AOX2, AOX3 and AOX4; Arath AOX1/AOX2/AOX3/AOX4 ?Arabidopsis thaliana AOX1, AOX2, AOX3 and AOX4; Lyces AOX1/AOX2/AOX3 ?Lycopersicon esculentum (tomato) AOX1, AOX2 and AOX3; Zeama AOX1/AOX2 ?Zea mays AOX1 and AOX2; Xenla AOX1 ?Xenopus laevis AOX1; Gorgo AOX1 ?Gorilla gorilla AOX1. All other abbreviations are as in Table 1. At present, it is unclear whether Macaca mulatta AOX4 is a functional gene product.The evolution of vertebrate aldehyde oxidases (Figure 2) is characterised by a first phase of asynchronous gene multiplication events, which started in certain birds. Fishes (Danio rerio) and amphibians (Xenopus laevis) are endowed with a single functional aldehyde oxidase gene. The corresponding gene products show the highest level of amino acid identity to the rodent AOX1 isoenzyme, supporting an orthologous relationship. D. rerio or X. laevis AOX1 has the conserved 35/36 exon structure typical of all vertebrate aldehyde oxidase genes. In addition, fish AOX1 and XOR map to different chromosomes, which is also characteristic of all vertebrates except primates. Some avians (chicken) show evidence of a gene duplication event involving AOX1 and resulting in theproduction of a new synthenic gene (on chromosome 7), which we named aldehyde oxidase homologue (AOH).22 AOH is characterised by an identical exon/intron structure, with perfect conservation of exon/intron junctions along the coding sequence. The amino acid sequences of chicken AOX1 and AOH protein products are approximately 60 per cent identical and only more distantly related to the corresponding XOR enzyme (40 per cent identity). The presence of two aldehyde oxidase genes in birds does not seem to be a general phenomenon. In fact, a BLAST search indicates that the zebra finch, Taeniopygia guttata, has a single AOX1 locus on chromosome 7 (Table 1 and Figure 2). Moving up along the evolutionary ladder to marsupials (Monodelphis domestica, opossum),# HENRY STEWART PUBLICATIONS 1479 ?364. HUMAN GENOMICS. VOL 4. NO 2. 119 ?30 DECEMBERUPDATE ON GENE COMPLETIONS AND ANNOTATIONSGarattini, Fratelli and TeraoFigure 2. Aldehyde oxidase genes in vertebrates. The figure contains a schematic representation of the aldehyde oxidase genes PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/29072704 in selected vertebrates for which complete or almost complete genomic sequence data are available. Orthologous genes are indicated with the same sha.