PUBLICATION

Evolutionary diversity of vertebrate small heat shock proteins

Authors
Franck, E., Madsen, O., van Rheede, T., Ricard, G., Huynen, M.A., and de Jong, W.W.
ID
ZDB-PUB-080218-31
Date
2004
Source
Journal of molecular evolution   59(6): 792-805 (Journal)
Registered Authors
Keywords
α-Crystallin, Phylogeny, Genome duplication, Intron evolution, Head-to-head genes, Small heat shock proteins, Moonlighting
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Base Pairing
  • Base Sequence
  • Computational Biology
  • DNA Primers
  • Databases, Genetic
  • Evolution, Molecular*
  • Genetic Variation*
  • Heat-Shock Proteins/genetics*
  • Likelihood Functions
  • Models, Genetic
  • Molecular Sequence Data
  • Phylogeny*
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Species Specificity
  • Vertebrates/genetics*
PubMed
15599511 Full text @ J. Mol. Evol.
Abstract
All vertebrates express multiple small heat shock proteins (sHsps), which are important components of the cellular chaperoning machinery and display a spectacular diversity of functions. This ranges from remodeling the cytoskeleton and inhibiting apoptosis to serving as structural proteins in eye lens and sperm tail. Most information is available for the 10 known mammalian sHsps, formally named HspB1-B10. Only three of them (Hsp27/B1, alphaA-crystallin/B4, alphaB-crystallin/B5) have been reported from nonmammalian vertebrates, while an apparent paralog, Hsp30/B11, is found in frogs and teleost fish. To reconstruct the evolutionary diversification of the sHsps in vertebrates, we searched for additional sHsps in genome, protein, and EST databases and sequenced some avian and amphibian sHsps (HspB2, Hsp30/B11). The urochordate Ciona intestinalis was included in the search, as the outgroup of vertebrates. Orthologs of seven mammalian sHsps were now found in other vertebrate classes. Two novel sHsps, named HspB11 and HspB12, were recognized in birds, and four novel sHsps, named HspB12-B15, in teleost fish. Secondary structure predictions of orthologous sHsps from different vertebrate classes indicate conservation of the beta-sandwich structure of the functionally important C-terminal "alpha-crystallin domain," while the N-terminal domains generally have alpha-helical structures, despite their pronounced sequence variation. The constructed chordate sHsp tree is supported by shared introns, indels, and diagnostic sequences. The tree distinguishes putative orthologous and paralogous relationships, which will facilitate the functional and structural comparison of the various vertebrate sHsps. The 15 recognized paralogous vertebrate sHsps reflect the period of extensive gene duplications early in vertebrate evolution. Eleven of these sHsps are grouped in a clade that might be specific for chordates. It is inferred that at least 13 intron insertions have occurred during the evolution of chordate sHsp genes, while a single ancient intron is maintained in some lineages, in line with the general trend of massive intron gain before or during early vertebrate radiation. Interesting is the occurrence of several head-to-head located pairs of chordate sHsp genes.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping