ZFIN ID: ZDB-PUB-050506-1
gammaN-crystallin and the evolution of the betagamma-crystallin superfamily in vertebrates
Wistow, G., Wyatt, K., David, L., Gao, C., Bateman, O., Bernstein, S., Tomarev, S., Segovia, L., Slingsby, C., and Vihtelic, T.
Date: 2005
Source: The FEBS journal   272(9): 2276-2291 (Journal)
Registered Authors: Vihtelic, Thomas
Keywords: none
MeSH Terms:
  • Algorithms
  • Amino Acid Sequence
  • Animals
  • Crystallins/chemistry
  • Crystallins/classification
  • Crystallins/genetics*
  • Crystallins/metabolism
  • Evolution, Molecular*
  • Eye/anatomy & histology
  • Eye/metabolism
  • Gene Duplication
  • Gene Expression Regulation
  • Lens, Crystalline/chemistry
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Multigene Family
  • Phylogeny
  • Protein Isoforms/genetics*
  • Protein Isoforms/metabolism
  • Recombinant Proteins/genetics
  • Recombinant Proteins/metabolism
  • Sequence Alignment
  • Tissue Distribution
  • Zebrafish
PubMed: 15853812 Full text @ FEBS J.
The beta and gamma crystallins are evolutionarily related families of proteins that make up a large part of the refractive structure of the vertebrate eye lens. Each family has a distinctive gene structure that reflects a history of successive gene duplications. A survey of gamma-crystallins expressed in mammal, reptile, bird and fish species (particularly in the zebrafish, Danio rerio) has led to the discovery of gammaN-crystallin, an evolutionary bridge between the beta and gamma families. In all species examined, gammaN-crystallins have a hybrid gene structure, half beta and half gamma, and thus appear to be the 'missing link' between the beta and gamma crystallin lineages. Overall, there are four major classes of gamma-crystallin: the terrestrial group (including mammalian gammaA-F); the aquatic group (the fish gammaM-crystallins); the gammaS group; and the novel gammaN group. Like the evolutionarily ancient beta-crystallins (but unlike the terrestrial gammaA-F and aquatic gammaM groups), both the gammaS and gammaN crystallins form distinct clades with members in fish, reptiles, birds and mammals. In rodents, gammaN is expressed in nuclear fibers of the lens and, perhaps hinting at an ancestral role for the gamma-crystallins, also in the retina. Although well conserved throughout vertebrate evolution, gammaN in primates has apparently undergone major changes and possible loss of functional expression.