Retention/ loss of duplicate genes. Therefore, within the zebrafish D. rerio, there’s one CB1 gene and two CB2 genes, whereas inside the puffer fish Fugu rubripes, you will find two CB1 genes and a single CB2 gene. Nevertheless, the functional significance in the differential retention of duplicate CB1 or CB2 genes in unique teleost lineages is at the moment unknown [73,74]. To date, you can find no published reports of CB1 and CB2 genes in the most basal from the extant vertebrate ordersthe chondrichthyes (e.g. sharks and rays) and the agnathans (e.g. lampreys and hagfish). However, unpublished genome sequence data are out there for the elephant shark Callorhinchus milii (http://eshark genome.imcb.astar.edu.sg/) plus the sea lamprey Petromyzon marinus (http://genome.wustl.edu/genomes/view/ petromyzon_marinus), and in each species, a gene encoding a CB1type receptor might be found. Interestingly, a CB2type receptor gene is just not evident in the currently accessible genome sequence data, which may possibly simply reflect incomplete sequence information or maybe much more interestingly may reflect loss of CB2 receptor genes in these basal vertebrates. Genes encoding CB1/CB2type receptors happen to be discovered in the invertebrate groups which are most closely associated to the vertebrates (urochordates, e.g. CiCBR in Ciona intestinalis; cephalochordates, e.g. BfCBR inReview. Evolution and comparative neurobiology M. R. Elphick Branchiostoma floridae) but not in the nonchordate invertebrate phyla [73,75 78]. Thus, it seems that CB1/CB2type receptors are distinctive for the phylum Chordata and, as such, they’ve a rather restricted phylogenetic distribution in the animal kingdom. (b) The phylogenetic distribution of diacylglycerol lipases The antiquity of DAGLs is evident inside the strategy that led for the discovery of your mammalian enzymes DAGLa and DAGLbthe sequence of a DAGL originally identified in the bacterium Neu-P11 Sodium Channel Penicillium was utilized to identify associated proteins in BLAST searches in the human genome sequence [17]. This indicates that DAGLs are an ancient enzyme household that originated in prokaryotes. Submission of human DAGLa and human DAGLb as query sequences in BLAST searches from the GenBank protein database reveals orthologues of each isoforms in deuterostomian invertebrates and protostomian invertebrates. As a result, the gene duplication that gave rise to DAGLa or DAGLb dates back at the least as far because the common ancestor of extant bilaterian animals. (c) The phylogenetic distribution of monoacylglycerol lipase MAGL was originally found on account of its part in fat metabolism [79] and subsequently, it was proposed that MAGL may perhaps regulate 2AG levels in the brain [20]. Submission of human MAGL as a query sequence in BLAST searches of the GenBank protein database reveals orthologues inside a wide array of animal species, such as deuterostomian invertebrates, protostomian invertebrate and basal invertebrates for example cnidarians (Butylated hydroxytoluene Autophagy Nematostella vectensis) and placozoans (Trichoplax adhaerens). Therefore, MAGL was present inside the prevalent ancestor of extant animals. Nevertheless, there has been loss of MAGL in some lineages; as an example, in Drosophila along with other insects. Interestingly, MAGL is also identified in poxviruses, which is probably a consequence of horizontal gene transfer from host species [80]. (d) The phylogenetic distribution of NAPEPLD as an enzyme implicated in anandamide biosynthesis Even though evaluation of NAPEPLDknockout mice indicates that NAPEPLD is not responsible for synthesis in the bulk of anandamide within the brain [2.
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