PUBLICATION

Evolution of thermoTRP ion channel homologs in vertebrates

Authors
Saito, S., and Shingai, R.
ID
ZDB-PUB-060825-18
Date
2006
Source
Physiological Genomics   27(3): 219-230 (Journal)
Registered Authors
Keywords
temperature-sensitive ion channel, vertebrate, comparative genomics, gene duplication, phylogenetic analyses
MeSH Terms
  • Animals
  • Chickens/genetics
  • Evolution, Molecular*
  • Genome
  • Genomics*
  • Humans
  • Phylogeny
  • TRPC Cation Channels/genetics*
  • TRPC Cation Channels/physiology
  • Temperature
  • Tetraodontiformes/genetics
  • Thermoreceptors
  • Transient Receptor Potential Channels/genetics*
  • Transient Receptor Potential Channels/physiology
  • Vertebrates/genetics*
  • Xenopus/genetics
  • Zebrafish/genetics
PubMed
16926268 Full text @ Physiol. Genomics
Abstract
In mammalian thermosensation, nine temperature-sensitive ion channels which are activated by distinct temperature thresholds have been identified as thermosensors. These ion channels belong to the transient receptor potential (TRP) superfamily, and are referred to as 'thermoTRPs' (TRPV1, TRPV2, TRPV3, TRPV4, TRPM2, TRPM4, TRPM5, TRPM8, and TRPA1). To elucidate the evolutionary processes of thermoTRPs, we conducted comprehensive searches for mammalian thermoTRP gene homologs in the draft genome sequences of chicken (Gallus gallus), western clawed frog (Xenopus tropicalis), zebrafish (Danio rerio), and pufferfish (Fugu rubripes). Newly identified homologs were compared to known thermoTRPs, and phylogenetic analyses were conducted. Our comparative analyses revealed that most of the mammalian thermoTRP members already existed in the common ancestor of fishes and tetrapods. Tetrapods shared almost the same repertoire, except that the western clawed frog expanded TRPV4s (six copies) and TRPM8s (two copies), which were diversified considerably. Comparisons of nonsynonymous and synonymous substitution rates among TRPV4s suggested that one copy of the TRPV4 channel in the western clawed frog retained its original function, while the other copies diversified and obtained slightly different properties. In fish lineages, several members of thermoTRPs have duplicated in the whole genome duplication occurred in the ancestral ray-finned fish, however, some of the copies have subsequently been lost. Furthermore, fishes do not possess the three members of thermoTRPs existed in mammals, e. g. thermoTRPs activated by noxious heat, warm, and cool temperatures. Our results suggest that thermosensation mechanisms have changed through vertebrate evolution with respect to thermosensor repertoires. Key words: gene duplication, phylogenetic analyses, comparative genomics, vertebrate, temperature-sensitive ion channel.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping