POSITIONAL CLONING OF HEREDITARY CATARACTS IN MICE

我们对日本发现的两种小鼠遗传性白内障的致病基因进行了定位克隆。这些基因被认为与器官发生和维持晶状体透明度有关。根据晶状体破裂(RLC)的精细定位结果，我们从RIKEN开发的小鼠全长cDNA百科全书中获得了多个位于MAP位置的cDNA克隆。其中一个克隆rlc1与正常的cdna序列相比，有27bp的缺失。该缺失是RLC突变体所特有的。兔抗RLCL产物C末端多肽的血清在晶状体中检测到一个110 kDa的多肽。免疫组织化学显示该抗体在晶状体上皮、神经系统等组织中有独特的分布。白内障的发生机制目前正在研究中。另一方面，在Nakano白内障(NCT)中，同样的定位方法显示NCTL基因有13bp的缺失。这一缺失在NK11中是保守的，NK11是由NEL提供的已建立的晶状体上皮细胞系。仔细检查与MSM交叉的N2中的晶状体，发现晶状体混浊在混浊和潜伏期的分布方面有两种不同的形式。我们可以在CHR上定位两个决定NCT白内障亚型的修饰基因座。3和10.为了进一步证实这些缺失确实是致病突变，本实验室正在进行正常全长cDNA的挽救和靶向实验。

We performed positional cloning of the genes responsible for two mouse hereditary cataracts found in Japan. These genes are supposedly involved in organogenesis and maintenance of transparency of the lens. According to the results of fine mapping of Rupture of lens cataract (RLC), we sequenced a number of the cDNA clones at the map positions obtained from the mouse full-length cDNA encyclopedia developed by RIKEN. One of cDNA clones, rlcl, was found to have deletion of 27 bp, when compared with the normal cDNA sequence. This deletion was specific to RLC mutant. Rabbit antiserum to the C-terminus peptide of rlcl product detected a 110 kDa polypeptide in the lens. Immunohistochemistry with this antiseum revealed unique distribution in lens epithelium, nervous system and other tissues. Mechanism of cataractgenesis is now under investigation. On the other hand, the same positional approach in Nakano cataract (NCT) demonstrated a 13 bp deletion in nctl cDNA. This deletion was conserved in NK11, an established cell line of lens epithelium provided from NEL Careful examination of the lenses in N2 cross to MSM revealed two distinct forms of lens opacity in respect to distribution of cloudiness and latent period. We could map two modifier loci determining the subtypes of NCT cataract on Chr. 3 and 10.To further confirm that these deletions are indeed causative mutation, rescue with normal full size cDNA and targeting experiments are now in progress in this laboratory.