dfh is a Drosophila homolog of the Friedreich's ataxia disease gene

A putative Drosophila homolog of the Friedreich's ataxia disease gene (FRDA ) has been cloned and characterized; it has been named Drosophila frataxin homolog (dfh). It is located at 8C/D position on X chromosome and is spread over 1 kb, a much smaller genomic region than the human gene. Its genomic organization is simple, with a single intron dividing the coding region int o two exons. The predicted encoded product has 190 amino acids, being consi dered a frataxin-like protein on the basis of the sequence and secondary st ructure conservation when compared with human frataxin and related proteins from other eukaryotes. The closest match between the Drosophila and the hu man proteins involved a stretch of 38 amino acids at C-terminus, encoded by dfh exon 2, and exons 4 and 5a of the FRDA gene, respectively. This highly conserved region is very likely to form a functional domain with a beta sh eet structure flanked by alpha -helices where the sequence is less conserve d. A signal peptide for mitochondrial import has also been predicted in the Drosophila frataxin-like protein, suggesting its mitochondrial localizatio n, as occurs for human frataxin and other frataxin-like proteins described in eukaryotes. The Drosophila gene is expressed throughout the development of this organism, with a peak of expression in 6-12 h embryos, and showing a spatial ubiquitous pattern from 4 h embryos to the last embryonic stage e xamined. The isolation of dfh will soon make available specific dfh mutants that help in understanding the pathogenesis of FRDA. (C) 2000 Elsevier Sci ence B.V. All rights reserved.