Mouse Models for the Dissection of CHD7 Functions in Eye Development and the Molecular Basis for Ocular Defects in CHARGE Syndrome
Mouse Models for the Dissection of CHD7 Functions in Eye Development and the Molecular Basis for Ocular Defects in CHARGE Syndrome
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DOI：
10.1167/iovs.15-18069
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发表时间：
2015-12-01
影响因子：
4.4
通讯作者：
Martin, Donna M.
中科院分区：
文献类型：
--
作者：
Gage, Philip J.;Hurd, Elizabeth A.;Martin, Donna M.
目的. CHARGE综合征（眼缺损、心脏缺陷、软骨闭锁、生长和/或发育迟缓、生殖器和/或泌尿道异常、耳异常和耳聋）是仅次于Usher综合征的第二大致盲原因。CHD 7中的杂合突变导致70%至90%的患者发生CHARGE综合征。我们测试了这样的假设：组织特异性突变小鼠为从分子水平剖析眼睛发育过程中的CHD 7功能提供了模型。方法。条件Chd 7（flox）等位基因与组织特异性Cre转基因一起交配。免疫组织化学被用来确定正常的CHD 7模式在早期的眼睛原基和评估Chd 7突变体的区域特异性蛋白标记物的表达。CHD 7存在于眼睛的神经外胚层和表面外胚层中。从神经和表面外胚层缺失导致严重畸形的眼睛，通常缺乏可识别的视杯结构和小晶状体。神经外胚层的缺失导致类似的缺陷。从表面外胚层缺失导致眼睛具有较小的晶状体。透镜组织和神经外胚层的主要亚类存在于从神经外胚层条件性缺失Chd 7之后。视裂的闭合依赖于神经外胚层内Chd 7基因的剂量。眼睛的发育需要多种胚胎组织中的CHD 7。透镜的发展需要CHD 7在表面外胚层，而视杯和柄形态发生需要CHD 7在神经外胚层。对于神经外胚层内的主要亚类的规范，CHD 7不是绝对必需的。与人类一样，小鼠的正常眼发育对Chd 7单倍不足敏感。这些数据表明Chd 7突变小鼠是用于确定CHARGE综合征中眼部缺陷的分子病因学的模型。
PURPOSE. CHARGE syndrome (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary tract abnormalities, and Ear abnormalities and deafness) is the second-leading cause of deaf-blindness after Usher syndrome. Heterozygous mutations in CHD7 cause CHARGE syndrome in 70% to 90% of patients. We tested the hypothesis that tissue-specific mutant mice provide models for molecularly dissecting CHD7 functions during eye development.METHODS. The conditional Chd7(flox) allele was mated together with tissue-specific Cre transgenes. Immunohistochemistry was used to determine the normal CHD7 pattern in the early eye primordia and to assess Chd7 mutants for expression of region-specific protein markers.RESULTS. CHD7 is present in the neural ectoderm and surface ectoderm of the eye. Deletion from neural and surface ectoderm results in severely dysmorphic eyes generally lacking recognizable optic cup structures and small lenses. Deletion from the neural ectoderm results in similar defects. Deletion from the surface ectoderm results in eyes with smaller lenses. Lens tissue and the major subdivisions of the neural ectoderm are present following conditional deletion of Chd7 from the neural ectoderm. Closure of the optic fissure depends on the Chd7 gene dose within the neural ectoderm.CONCLUSIONS. Eye development requires CHD7 in multiple embryonic tissues. Lens development requires CHD7 in the surface ectoderm, whereas optic cup and stalk morphogenesis require CHD7 in the neural ectoderm. CHD7 is not absolutely required for specification of the major subdivisions within the neural ectoderm. As in humans, normal eye development in mice is sensitive to Chd7 haploinsufficiency. These data indicate the Chd7 mutant mice are models for determining the molecular etiology of ocular defects in CHARGE syndrome.