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Corpus Systématique Animale

Titre du document

Characterization of ?-crystallin from the eye lens of bullfrog: Complexity of ?-crystallin multigene family as revealed by sequence comparison among different amphibian species

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Springer (journals)
Langue(s) du document
Type de document
Mots-clés d'auteur
  • ? -Crystallin
  • amphibian lens
  • polymerase chain reaction (PCR)
  • sequence comparison
  • multigene family
  • phylogenetic tree
Nom du fichier dans la ressource
Batraciens_v2b_00566, Mammiferes_v2b_02797, Poissons_v2b_005453
  • Shao-Fan Lu 1
  • Fu-Ming Pan 2
  • Shyh-Horng Chiou 1
  • 1) Laboratory of Crystallin Research, Institute of Biochemical Sciences, National Taiwan University, 10098, Taipei, Taiwan
  • 2) Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan

?-Crystallin is the major and most abundant lens protein present in the eye lens of lower vertebrates such as amphibian and piscine species. To facilitate structural characterization of?-crystallins isolated from the lens of the bullfrog (Rana catesbeiana), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses. cDNA encoding?-crystallin was then amplified using polymerase chain reaction (PCR) based on two primers designed according to the relatively conserved N- and C-terminal sequences of known?-crystallins from teleostean fishes. PCR-amplified product corresponding to?-crystallin isoforms was obtained, which was then subcloned in pUC18 vector and transformed intoEscherichia coli strain JM109. Plasmids containing amplified?-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing several clones containing DNA inserts of about 0.54 kb revealed the presence of two isoforms with an open reading frame of 534 base pairs, covering two?-crystallins each with a deduced protein sequence of 177 amino acids including the translation-initiating methionine. These?-crystallins of pI 6.364 and 6.366 contain a low-methionine content of 2.81%, in contrast to 11–16% obtained for those?-crystallins with high-methionine content from most teleostean lenses. Pairwise sequence comparison of bullfrog?-crystallins with those published sequences of?-crystallins from carp, shark,Xenopus and anotherRana frog, bovine, and human lenses indicates that there is only 46–63% sequence similarity among these species, revealing that amphibians possess a very complex and heterogeneous group of?-crystallins even from closely related species ofRana frogs. The sequence analysis and comparison of various isoforms of the frog?-crystallin family provide a firm basis for identifying these lens proteins as members of a multigene family more complex than that reported for mammalian?-crystallins.

Catégories Science-Metrix
  • 1 - health sciences
  • 2 - biomedical research
  • 3 - biophysics
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
Catégories Scopus
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Biochemistry
Identifiant ISTEX

Journal of Protein Chemistry

Année de publication
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Score qualité du texte
  • Batraciens
  • Mammiferes
  • Poissons
Type de publication
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