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Two ovine BAC clones and a connecting long-range PCR product, jointly spanning approximately 250 kb and representing most of the MULGE5-OY3 marker interval known to contain the clpg locus, were completely sequenced. The resulting genomic sequence was aligned with its human ortholog and extensively annotated. Six transcripts, four of which were novel, were predicted to originate from within the analyzed region and their existence confirmed experimentally: DLK1, DAT, GTL2, PEG11, antiPEG11, and MEG8. RT-PCR experiments performed on a range of tissues sampled from an 8-wk-old animal demonstrated the preferential expression of all six transcripts in skeletal muscle, which suggests that they are under control of common regulatory elements. The six transcripts were also shown to be subject to parental imprinting: DLK1, DAT, and PEG11 were shown to be paternally expressed and GTL2, antiPEG11, and MEG8 to be maternally expressed.

Autosomal dominant familial spastic paraplegia (AD-FSP) is a genetically heterogeneous neurodegenerative disorder characterized by progressive spasticity of the lower limbs. Three loci on chromosome 14q (SPG3), 2p (SPG4), and 15q (SPG6) were shown to be responsible for AD-FSP. Analysis of recombination events in three SPG3-linked families allowed us to narrow the critical interval from 9 to 5 cM. An approximately 5-Mb YAC contig comprising 32 clones and 90 STSs was built from D14S301 to D14S991, encompassing this region of 14q21. Fifty-six ESTs assigned previously to this region with radiation hybrid (RH) panels Genebridge 4 and G3 were precisely localized on the YAC contig. The 90 STSs positioned on the contig were tested on the TNG RH panel to compare our YAC-based map with an RH map at a high level of resolution. Comparison between our map and the whole genome mapping data on this interval of chromosome 14q is discussed.

Human genes containing triplet repeats have been demonstrated to be involved in several neurodegenerative diseases by expansion of the repeat in succeeding generations. To identify novel genes involved in such pathologies, we have isolated transcripts containing (CAG/CTG)n repeats using two approaches. First, we screened 4 x 10(6) clones representing 10 copies of a human testis cDNA library using a (CAG)14 oligonucleotide probe. Among the 910 clones identified, the 243 clones with the strongest hybridization signal were sequenced partially from 3' or 5' ends. This provided us with 251 partial sequences that grouped into clusters corresponding to 39 genes, of which 19 represent unknown species. Second, we selected 203 additional ESTs containing (CAG/CTG)n repeats representing 121 clusters from the IMAGE consortium infant brain cDNA library. From these two series of sequences, we have localized 95 genes on human chromosomes using a panel of whole genome radiation hybrid (Genebridge 4). These genes are located on all of the chromosomes except for chromosome X, the highest density being observed on chromosome 19.