Abstract
Abstract: :
Canine early retinal degeneration (erd), a model of human retinitis pigmentosa, maps to CFA27 (previous nomenclature CFA16, CFA29) in an interval corresponding to part of HSA12. Purpose: To refine the erd interval, determine gene order within the region of interest and evaluate positional candidate genes for erd disease. Method: Genetic and RH mapping strategies were applied for finescale mapping of erd. Six genes located on HSA12p in the region corresponding to the erd interval of CFA27 were selected and mapped on canine RH3000 panel together with a set of published markers from CFA27 RH MAP5000. SIAT8A, SHARP-1 and BICD1 probes were used for canine BAC library screening and identification of polymorphic markers. SNPs and microsatellites were used for linkage analyses of 11 erd informative pedigrees. Results: Canine genes: SIAT8A, SHARP-1, BICD1, BCAT1, LRMP1 and ARG99 were localized on CFA27 RH Map3000. Comparison of the human and dog maps shows extensive conservation between HSA12p and CFA27 but some differences in gene order are detected. Gene-specific polymorphic markers were identified and used for genetic analyses of erd. Meiotic data confirmed the gene order observed on CFA27 RH MAP3000. One recombination was observed between BICD1 and erd and another between erd and LRMP1. No recombinations were detected between erd and two markers: SHARP-1 and REN277K09. Four human DNA contigs covering the region from BICD1 to LRMP1 were blasted against non-redundant and EST databases. Several positional candidate genes for erd disease were identified: SHARP-1 (DEC-2) - a bHLH transcription repression protein; HOJ-1 - a probable cell growth or differentiation regulator; and fetal retina expressed EST AA679339. Conclusion: Genetic and RH3000 maps for the erd region of CFA27 were developed and the zero recombination interval for erd was significantly reduced. Several positional candidate genes were selected and their potential role in erd is being tested. CR: N Supported by EY06855 and EY13132, the Foundation Fighting Blidness, American Border Collie Association , Morris Animal Foundation/ The Seeing Eye, Inc., and the Van Sloun Fund for Canine Genetics Research
Keywords: 562 retinal degenerations: hereditary • 335 candidate gene analysis • 418 gene mapping