Abstract
Abstract: :
Purpose: CLUL1 is a novel retinal specific gene we previously identified by suppression subtractive hybridization as a reduced level of expression in prcd affected canine retinas. In this study we sought to characterize the genomic organization of the CLUL1 gene of human and dog, and identify potential regulatory elements conserved between the species. Methods: Human CLUL1 cDNA was retrieved by hybridization screening of a human retinal cDNA library. Splice variants of the canine cDNA were isolated by 5' and 3' RACE. Introns of canine CLUL1 were amplified by long-range PCR and sequenced. Ortholog sequences of human was retrieved from NCBI database. Results: The full length human and canine cDNAs comprise 1764 bp and 1812 bp respectively. From deduced polypeptide sequence (human 466 aa, dog 465 aa), human and dog share 73% identities. The CLUL1 gene comprises nine exons spanning about 33 kb. CLUL1 has been mapped to HSA18p11.3 in man, and to the homologous region in canine CFA4. Analysis of splice donor, acceptor and intron sequences revealed highly conserved regions, indicating potential regulatory elements. Northern blot analysis demonstrated reduced expression levels in XLPRA2 diseased dog retinas. Conclusion: The CLUL1 gene is highly conserved between human and dog. Its retina-specific expression and reduced expression in PRA retinas suggest it has an important role both in normal retinal function and in retinal disease.
Keywords: 417 gene/expression • 554 retina • 517 photoreceptors