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Cloning of causative gene responsible for a new ingerited cataract in the mouse

克隆导致小鼠新发白内障的致病基因

基本信息

批准号：
12680682
负责人：
MAEDA Yukiko Y.
金额：
$ 2.37万
依托单位：
Tokyo Metropolitan Organization for Medical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

We discovered a new mutant mouse, RCT (Rinshoken Cataract), with a congenital cataract in strain SJL/J. Mouse models are effective tools to map human cataract genes to specific chromosomal region through conserved linkage between the human and the mouse, and consequently to elucidate the functions of their proteins. Our experimental results are : 1.Characteristics of RCT cataract. The opacity of the lens associated with microphthalmia could be observed visually at 3 to 3.5 months of age. Marked degeneration of the lens, including loss of the fine structure of the lens fibers and swelling of epithelial cells with vacuoles of various sizes in the cortex was detected. Histological changes in the lens were first observed at 2 days after birth. No sex-related differences were detected, and normal phenotypes in the F_<1> progeny of RCT and other normal strains. 2.Interval mapping. The chromosomal localization of causative gene was determined by interval mapping by using intersubspecific backcross progeny of RCT and MSM/Ms, an inbred strain from the Japanese wild mouse Mus musculus molossinus. Backcross progeny were divided into three groups according to phenotype : mice (1) with an early onset-cataract, which can be detected visually as in RCT mice, (2) with a late onset-cataract histologically but not visually, and (3) with normal lens. Allele combinations of two recessive genes, ret on chromosome 4 and mrct (a modifier of rct) on chromosome 5 regulated three phenotypes. 3.Gene isolation. To isolate ret gene, linkage analysis using more 1000 heads of (RCT x MSM/Ms) F_<2> mice was done, and BAC contig including the rct locus in the range of approximately 600 kbp was constructed almost. Six ESTs, which may be a candidate of rct gene, were found in the BAG contig.

我们在SJL/J品系中发现了一种新的先天性白内障突变小鼠RCT（Rinshoken Cataract）。小鼠模型是通过人与小鼠之间的保守连锁将人类白内障基因定位到特定染色体区域并进而阐明其蛋白质功能的有效工具。实验结果如下：1. RCT白内障的特征。在3至3.5月龄时，可目视观察到与小眼症相关的透镜不透明。检测到透镜明显变性，包括透镜纤维的精细结构丢失和上皮细胞肿胀，皮质中存在各种大小的空泡。透镜的组织学变化在出生后2天首次观察到。RCT与其他正常株的F_后代无性别差异，表型正常<1>。2.区间映射。利用日本野生小家鼠（Mus musculus molossinus）近交系MSM/Ms与RCT的亚种间回交后代，通过区间作图法对致病基因进行了染色体定位。根据表型将回交后代分为三组：（1）具有早发性白内障的小鼠，其可以如RCT小鼠中那样视觉检测到，（2）具有组织学上但视觉上不能检测到的迟发性白内障，和（3）具有正常透镜。4号染色体上的ret和5号染色体上的mrct（rct的修饰基因）这两个隐性基因的等位基因组合调节三种表型。3.基因分离。为了分离ret基因，对1000多只（RCT x MSM/Ms）F_小鼠进行了连锁分析<2>，构建了包含rct基因的BAC重叠群，其大小约为600 kbp。在BAG重叠群中发现了6个可能是rct基因候选的EST。