title: The eye lens crystallins: ambiguity as evolutionary strategy.
abstract: Comparative studies of the different families of lens-specific proteins of the vertebrates, the crystallins, and their genes reveal several interesting evolutionary features. The origin of alpha-crystallin can be traced back to the small heat shock proteins, while the superfamily of beta gamma-crystallins shows structural similarities with a bacterial spore coat protein. The crystallins display a great diversity within and between species, as well as during development. Ambiguous transcription, mRNA-processing, and translation contribute to this diversity of the crystallins and their expression. These mechanisms include the occurrence of atypical poly-A addition signals, alternative splicing, and the use of two initiation codons on a single mRNA.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D003459:Crystallins / Q000235:genetics*; D005796:Genes; D046911:Macromolecular Substances; D011401:Promoter Regions, Genetic; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D003459:Crystallins; D046911:Macromolecular Substances