KIAA1753, a Gene Potentially Involved in Progressive Rod-cone Degeneration (prcd)

Abstract

Abstract: : Purpose: Progressive rod-cone degeneration (prcd), an autosomal recessive retinal degeneration of dogs, maps to CFA9, a region that shows conservation of synteny with human HSA17qter. KIAA1753 is a gene of unknown function that has been localized to 17q25.3 in humans, and is therefore a candidate gene for prcd. Based on both human and canine sequences obtained from a dog genomic library, the canine coding part of KIAA1753 cDNA has been cloned and sequenced in a non prcd-affected dog. In parallel, the KIAA1753 cDNA in a prcd-affected animal was cloned and compared to the non affected dog sequences to look for SNPs and disease-associated sequence changes. Methods: Partial canine KIAA1753 sequences obtained from a dog BAC genomic library was completed by using a PCR-cloning approach to isolate full-length KIAA1753 cDNA. Total retinal RNA was extracted from prcd non-affected and prcd-affected dogs. The RNA were retrotranscribed into a single strand cDNA. KIAA1753 cDNA sequences were then amplified by PCR using dog KIAA1753 sequence specific primers. PCR products corresponding to expected DNA size were cloned and sequenced. Results: The coding sequence of KIAA1753 in dogs is 1238 bp and encodes a protein of 412 amino acids. It is composed of 9 exons (1 to 9). The characterized 1103 bp region of canine KIAA1753 cDNA spans from coding exon 2 to the end of exon 9,corresponding to 96% of the predicted coding sequence. It shows 94 % homology to the human KIAA1753 cDNA sequences. Comparative analysis of cDNA sequences showed no difference between the prcd-affected and the non affected dogs. Conclusions: No changes in the nucleotide sequence were found in the coding region of KIAA1753 cDNA from prcd-affected and non affected dogs suggesting that KIAA1753 is not involved in the molecular mechanism leading to prcd. Because mutations in non coding sequences could be involved as well in the disease, we are now cloning and comparing sequences in the 5’and 3'untranslated regions (UTRs), and intronic sequences of the KIAA1753 gene.

Keywords: retinal degenerations: hereditary • animal model • gene mapping