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ZFIN ID: ZDB-PUB-091023-3
Evolution of receptors for growth hormone and somatolactin in fish and land vertebrates: lessons from the lungfish and sturgeon orthologues
Fukamachi, S., and Meyer, A.
Date: 2007
Source: Journal of molecular evolution   65(4): 359-372 (Journal)
Registered Authors: Meyer, Axel
Keywords: Somatolactin receptor (SLR), Growth hormone receptor (GHR), Lungfish, Sturgeon, Fish-specific genome duplication (FSGD), Synteny, Sub-functionalization
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • DNA Primers
  • Evolution, Molecular*
  • Fish Proteins/chemistry
  • Fish Proteins/genetics*
  • Fishes/genetics*
  • Glycoproteins/chemistry
  • Glycoproteins/genetics*
  • Molecular Sequence Data
  • Phylogeny
  • Pituitary Hormones/chemistry
  • Pituitary Hormones/genetics*
  • Receptors, Somatotropin/chemistry
  • Receptors, Somatotropin/genetics*
  • Sequence Homology, Amino Acid
  • Species Specificity
PubMed: 17917757 Full text @ J. Mol. Evol.
Two cognate hormones, growth hormone (GH) and somatolactin (SL), control several important physiological processes in vertebrates. Knowledge about GH and its receptor (GHR) has accumulated over the last decades. However, much less is known about SL and its receptor (SLR). SL is found only in fish (including lungfish), suggesting that it was present in the common ancestor of vertebrates, but was lost secondarily in the lineage leading to land vertebrates after the lungfish branched off. SLR was suggested to be a duplicated copy of GHR acquired only in teleosts via the fish-specific genome duplication (FSGD). This scenario (i.e., the existence of SL but not SLR in the vertebrate ancestors) is intriguing but contested. In this study, we first evaluated the plausibility of this scenario through synteny analyses and found that the loci for GHR and SLR are located in syntenic genomic positions, whereas the loci for GH and SL are not. Next, we cloned GHRs of lungfish and sturgeon, which possess SL but did not undergo the FSGD (i.e., they should not possess SLR). Their phylogenetic positions in the GHR/SLR gene tree further support the fish-specific scenario for the GHR-SLR duplication. Interestingly, their sequences share greater similarity with teleost SLRs and reptilian/amphibian GHRs than with the GHRs of mammals, birds, and teleosts. On the basis of these results, we discuss the validity of the nomenclature of the teleost-specific copy of GHR as SLR and an ancestral receptor(s) for SL before the evolution of SLR during the FSGD.