The zebrafish genome contains two distinct selenocysteine tRNA[Ser]Sec genes

Kyungpook National University, Daikyƫ, Daegu, South Korea
FEBS Letters (Impact Factor: 3.17). 08/1999; 454(1-2):16-20. DOI: 10.1016/S0014-5793(99)00767-X
Source: PubMed


The zebrafish is widely used as a model system for studying mammalian developmental genetics and more recently, as a model system for carcinogenesis. Since there is mounting evidence that selenium can prevent cancer in mammals, including humans, we characterized the selenocysteine tRNA[Ser]sec gene and its product in zebrafish. Two genes for this tRNA were isolated and sequenced and were found to map at different loci within the zebrafish genome. The encoding sequences of both are identical and their flanking sequences are highly homologous for several hundred bases in both directions. The two genes likely arose from gene duplication which is a common phenomenon among many genes in this species. In addition, zebrafish tRNA[Ser]sec was isolated from the total tRNA population and shown to decode UGA in a ribosomal binding assay.

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    • "Many duplicated genes were lost during evolution, while other duplicated zebrafish genes were retained. Two identical selenocysteine tRNA genes were found encoded in the zebrafish genome, which most likely evolved by duplication of the entire genome (Xu et al. 1999). However, since we found three homologues of human SelT and SelW, genome duplication could not be solely responsible for the evolution of these selenoprotein genes. "
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