Dekomien Gabriele, Epplen Jörg Thomas
Molecular Human Genetics, Ruhr-University, 44780 Bochum, Germany.
BMC Genet. 2002 Jul 17;3:12. doi: 10.1186/1471-2156-3-12.
Intronic DNA sequences of the canine arrestin (SAG) gene was screened to identify potential disease causing mutations in dogs with generalized progressive retinal atrophy (gPRA). The intronic sequences flanking each of the 16 exons were obtained from clones of a canine genomic library.
Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA sequence analyses we screened affected and unaffected dogs of 23 breeds with presumed autosomal recessively (ar) transmitted gPRA. In the coding region of the SAG gene 12 nucleotide exchanges were identified, 5 of which lead to amino acid substitutions (H14C; A111V; A113T; D259T; A379E). 7 other exonic substitutions represent silent polymorphisms (C132C; Q199Q; H225H; V247V; P264P; T288T and L293L). 16 additional sequence variations were observed in intronic regions of different dog breeds.
In several breeds, these polymorphisms were found in homozygous state in unaffected and in heterozygous state in affected animals. Consequently these informative substitutions provide evidence to exclude mutations in the SAG gene as causing retinal degeneration in 14 of the 23 dog breeds with presumed ar transmitted gPRA.
对犬类抑制蛋白（SAG）基因的内含子DNA序列进行筛选，以鉴定患有全身性进行性视网膜萎缩（gPRA）的犬类中潜在的致病突变。从犬类基因组文库的克隆中获得了16个外显子两侧的内含子序列。
我们使用聚合酶链反应-单链构象多态性（PCR-SSCP）和DNA序列分析，对23个品种中假定为常染色体隐性（ar）遗传的gPRA的患病和未患病犬进行了筛选。在SAG基因的编码区鉴定出12个核苷酸交换，其中5个导致氨基酸替换（H14C；A111V；A113T；D259T；A379E）。其他7个外显子替换代表沉默多态性（C132C；Q199Q；H225H；V247V；P264P；T288T和L293L）。在不同犬种的内含子区域还观察到另外16个序列变异。
在几个品种中，这些多态性在未患病动物中以纯合状态存在，在患病动物中以杂合状态存在。因此，这些信息性替换为排除SAG基因中的突变是23个假定为ar遗传的gPRA犬种中14个品种视网膜变性的病因提供了证据。
