Purpose: To determine the nucleotide sequence, amino acid sequence and tissue specificity of zebrafish alphaA-crystallin.
Methods: RACE, both 3' and 5', was used to clone the zebrafish alphaA-crystallin gene. The peptide sequence of the encoded protein was deduced and compared to cavefish, shark, amphibian, bird and human orthologues using the CLUSTAL W algorithm. alphaA-crystallin transcript was evaluated in brain, heart, lens, liver, skeletal muscle/skin, and spleen by semi-quantitative RT-PCR.
Results: The 173 amino acid sequence of zebrafish alphaA-crystallin was determined to be 73% and 86% similar to its human and cavefish orthologues, respectively. We detected high expression of zebrafish alphaA-crystallin in the lens and very low expression in liver and spleen.
Conclusions: Few amino acids identified as being functionally important to chaperone function differ between zebrafish and mammalian alphaA-crystallin. The expression of alphaA-crystallin is mainly confined to the lens in both taxa. These data suggest that zebrafish alphaA-crystallin plays a physiologically limited role outside of the zebrafish lens, similar to its mammalian orthologues.