Xiao-Mei Shi

Fluorescent in situ mapping of the murine deleted in split hand/split foot 1 (dss1) gene to Chromosome 6

Species: Mouse Locus name: deleted in split hand/split foot 1 Locus symbol: dssl Map position: 6A Method of mapping: Fluorescence in situ hybridization (FISH) Database deposit information: Genbank Accession # U41626 Molecular reagents used for mapping: A mouse phage clone was isolated from a 129 total genomic library with a full-length dssl cDNA [1] as probe. The phage clone was biotinylated with dATP and the BRL Bionick labeling kit [2], and used in FISH analysis according to previously described methods [2,3]. Previously idenafied homologs: Human DSS1 maps to 7@1.3q22.1 [1], and a human pseudogene DSS1P1 [4] has been mapped to Chromosome (Chr) 5q14 by FISH. Discussion: DSS1 was isolated as a candidate gene for split hand/ split foot malformation (SHFM1), which maps to human Chr 7q21.3-q22.1 [ 1 ]. The gene is highly conserved through evolution, and the mouse and human genes are 100% identical at the amino acid level, but the putative gene product has no significant homology to any known protein or protein motifs [I]. RNA in situ hybridization studies indicate that the gene is widely expressed during embryogenesis in the limb buds, branchial arches, skin, genital bud, and other tissues in which epithelial mesenchymal inductive interactions are critical for proper development [1]. Although a definitive biological role for this gene has not yet been determined, a mouse knockout model is being generated to address this question. Genes localized to human 7q21.3 and human 7q22.1 map to mouse Chr. 6 and 5 respectively [5], but the precise site of divergence is unknown. The gene order in human is: 7q21.3-CALCR-