Mapping and structure of DMXL1, a human homologue of the DmX gene from Drosophila melanogaster coding for a WD repeat protein

The DmX gene was recently isolated from the X chromosome of Drosophila mela nogaster. TBLASTN searches of the dbEST databases revealed sequences with a high level of similarity to DmX in a variety of different species, includi ng insects, nematodes, and mammals showing that DmX is an evolutionarily hi ghly conserved gene. Here we describe the cloning of the cDNA and the chrom osomal localization of one of the human homologues of DmX, Dmx-like 1 (DMXL 1). The human DMXL1 gene codes for a large mRNA of II kb with an open readi ng frame of 3027 amino acids. The putative protein belongs to the superfami ly of mo repeat proteins, which have mostly regulatory functions. The DMXL1 protein contains an exceptionally large number of WD repeat units. The DMX L1 gene is located on chromosome 5q22 as determined by radiation hybrid map ping and fluorescence in situ hybridization. Although the function of the D MXL1 gene and its homologues in other species remains to be discovered, the high level of evolutionary conservation together with the unusual structur e suggests that it probably has an important function. (C) 2000 Academic Pr ess.