Genotype-phenotype correlation of mouse Pde6b mutations
Genotype-phenotype correlation of mouse Pde6b mutations
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DOI：
10.1167/iovs.05-0254
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发表时间：
2005-09-01
影响因子：
4.4
通讯作者：
Cross, SH
中科院分区：
文献类型：
--
作者：
Hart, AW;McKie, L;Cross, SH
目的.在7个N-乙基-N-亚硝基脲（ENU）诱导的Pde6b基因突变等位基因中，确定导致视网膜变性的潜在分子缺陷，并分析这些新的视网膜色素变性模型中视网膜变性的时间尺度。构象敏感毛细管电泳和DNA测序用于鉴定Pde6b基因的突变。在出生后第25天至第10周的年龄范围内，使用视觉跟踪鼓进行视力测试。用间接检眼镜进行视网膜检查。处死动物，制备眼睛用于组织学分析。在Pde6b的7个新等位基因中鉴定出点突变：3个产生提前终止密码子，2个是错义突变，2个是剪接突变。三个终止密码子突变体和一个剪接突变体的表型与Pde6b（rd1）小鼠视网膜变性的发病速度没有区别，这表明它们是无效等位基因。然而，其余的等位基因表现出较缓慢的视网膜变性的发病，通过视力测试，眼底检查，和组织学，表明他们是亚型等位基因。这些数据证明了基因型和表型之间的相关性。四个突变体与严重的遗传病变有迅速发病的视网膜变性，确定眼底检查。这些小鼠与Pde6brd1小鼠无法区分，Pde6brd1小鼠在3周龄时有效失明。相比之下，较轻的遗传病变显示疾病进展较慢，并为社区提供了更接近人类视网膜色素变性的模型。
PURPOSE. To identify the underlying molecular defects causing retinal degeneration in seven N-ethyl-N-nitrosourea (ENU) induced mutant alleles of the Pde6b gene and to analyze the timescale of retinal degeneration in these new models of retinitis pigmentosa.METHODS. Conformation sensitive capillary electrophoresis and DNA sequencing were used to identify the mutations in the Pde6b gene. Visual acuity testing was performed with a visual-tracking drum at ages ranging from postnatal day 25 to week 10. Retinal examination was performed with an indirect ophthalmoscope. Animals were killed and eyes were prepared for histologic analysis.RESULTS. Point mutations in the seven new alleles of Pde6b were identified: Three generated premature stop codons, two were missense mutations, and two were splice mutations. The three stop codon mutants and one of the splice mutants had phenotypes indistinguishable from the Pde6b(rd1) mouse in rapidity of onset of retinal degeneration, suggesting that they are null alleles. However, the remaining alleles showed slower onset of retinal degeneration, as determined by visual acuity testing, fundus examination, and histology, indicating that they are hypomorphic alleles.CONCLUSIONS. These data demonstrate a correlation between genotype and phenotype. Four of the mutants with severe genetic lesions have rapid onset of retinal degeneration, as determined by fundus examination. These mice were indistinguishable from Pde6brd1 mice, which are effectively blind by 3 weeks of age. In contrast, the milder genetic lesions show a slower progression of the disease and provide the community with models that more closely mimic human retinitis pigmentosa.