Purpose: We are working to clone the gene responsible for X-linked retinoschisis (RS), a human hereditary disease that causes splitting through the inner retinal layers and leads to central and peripheral vision loss early in life. Our genetic linkage work has narrowed the RS interval to approximately 900 kb between markers AFM291w5 and (DXS1195, DXS418). We are identifying candidate genes for RS in this region. Methods: A positional cloning strategy is being used. Cosmid libraries were constructed using whole YAC DNA in SuperCos1 vector. Positive clones were selected using Cot-1 human DNA as the probe. Exon trapping and direct cDNA selection are being used for identification of expressed sequences. Exon trapping is carried out using GibcoBRL exon trapping system. Transcribed sequences are compared against data bank sequences using GCG and BLAST algorithms. Results: A cosmid library was generated from a nonchimeric 2 MB CEPH YAC 939h7 that includes our complete RS genetic interval. Eight clones show the presence of CpG islands, and we have identified several putative transcribed sequences by exon trapping. Positive signals have also been identified by direct hybridization screening with retinal cDNA libraries. At least two clones contain CA repeat regions that are being studied as possible new genetic markers for RS. Smaller YACS (yWXD1774 and ICRFy0922) in the RS interval are also being utilized. We are screening EcoR1 and Rsa1 restriction panels of 38 independent RS families for deletions using probes from the RS region. Conclusions: Analysis of candidate genes isolated using genomic DNA clones should lead to identification of the gene responsible for X-linked retinoschisis.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience