The lens protein alpha-B-crystallin of the blind subterranean mole-rat: high homology with sighted mammals

Blind subterranean mole rats, Spalax ehrenbergi, retain a subcutaneous, degenerated eye, which is visually non-functional but which does function in circadian entrainment. Crystallins, members of the small heat shock protein family, constitute approximately 90% of the water-soluble proteins of the transparent eye lens and are crucial for its optical properties, but they are also expressed in other tissues. In our attempt to understand the role of the eye in the blind mole-rat, we now describe the cloning, sequencing, and expression of the cDNA of alpha-B-Crystallin from two species of Spalax (S. galili and S. Judaei, with diploid chromosome numbers 2n=52 and 60, respectively). Spalax alpha- B-Crystallin is highly conserved. It is expressed in many tissues of Spalax, among them Spalax eye. The sequence of the cDNA of alpha-B-Crystallin in the eye and in the heart of Spalax is identical. Further studies are essential to clarify the role of this gene in the lens of an atrophied eye of a visually blind mammal.