Complete abolition of the retinal-specific guanylyl cyclase (retGC-1) catalytic ability consistently leads to leber congenital amaurosis (LCA).
Complete abolition of the retinal-specific guanylyl cyclase (retGC-1) catalytic ability consistently leads to leber congenital amaurosis (LCA).
复制标题
视网膜特异性鸟苷酸环化酶 (retGC-1) 催化能力的完全丧失始终会导致莱伯先天性黑蒙 (LCA)。
DOI：
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复制
发表时间：
2001
影响因子：
4.4
通讯作者：
J. Kaplan
中科院分区：
文献类型：
--
作者：
J. Rozet;I. Perrault;S. Gerber;S. Hanein;F. Barbet;D. Ducroq;E. Souied;Arnold Munnich;J. Kaplan
目的
Leber先天性黑蒙（LCA）是所有遗传性视网膜营养不良中最早和最严重的形式。1996年，目前的研究人员将与染色体17p13.1上的LCA 1基因座相关的家族中的疾病归因于光受体特异性鸟苷酸环化酶（retGC-1）基因的突变。到目前为止，已经在25个无关的家庭中发现了22种不同的突变，其中11种是错义突变。这是一份对9个错义突变进行功能分析的报告。
方法
产生cDNA构建体，其含有在患者中鉴定的与LCA 1基因座相关的retGC-1错义突变。突变体在COS 7细胞中表达，并测定其将三磷酸鸟苷（GTP）水解成环磷酸鸟苷（cGMP）的能力。
结果
位于催化结构域中的所有突变显示出环化酶活性的完全消除。相比之下，只有一个突变位于细胞外结构域也导致催化活性严重降低，而其他人表现出完全正常的活动。
结论
在患者中鉴定的与LCA 1基因座相关的突变中，超过一半是预期导致retGC-1活性完全消除的截短突变。关于错义突变，它们中的一半位于蛋白质的催化结构域中，也导致突变环化酶在体外完全不能将GTP水解成cGMP。相反，错义突变位于胞外结构域，除了一个影响起始密码子，显示正常的催化活性retGC-1。然而，考虑到与LCA 1基因座相关的所有患者均表现出相同的表型，可以假设所有错义突变对体内蛋白质活性具有与截短突变相同的显著后果。
PURPOSE
Leber congenital amaurosis (LCA) is the earliest and the most severe form of all inherited retinal dystrophies. In 1996, the current investigators ascribed the disease in families linked to the LCA1 locus on chromosome 17p13.1 to mutations in the photoreceptor-specific guanylyl cyclase (retGC-1) gene. So far, 22 different mutations, of which 11 are missense mutations, have been identified in 25 unrelated families. This is a report of the functional analyses of nine of the missense mutations.
METHODS
cDNA constructs were generated that contained the retGC-1 missense mutations identified in patients related to the LCA1 locus. Mutants were expressed in COS7 cells and assayed for their ability to hydrolyze guanosine triphosphate (GTP) into cyclic guanosine monophosphate (cGMP).
RESULTS
All mutations lying in the catalytic domain showed a complete abolition of cyclase activity. In contrast, only one mutation lying in the extracellular domain also resulted in a severely reduced catalytic activity, whereas the others showed completely normal activity.
CONCLUSIONS
More than half the mutations identified in patients related to the LCA1 locus are truncating mutations expected to result in a total abolition of retGC-1 activity. Concerning missense mutations, half of them lying in the catalytic domain of the protein also result in the complete inability of the mutant cyclases to hydrolyze GTP into cGMP in vitro. In contrast, missense mutations lying in the extracellular domain, except one affecting the initiation codon, showed normal catalytic activity of retGC-1. Nevertheless, considering that all patients related to the LCA1 locus displayed the same phenotype, it can be assumed that all missense mutations would have the same dramatic consequences on protein activity in vivo as truncation mutations.
人类 GCAP1 和 GCAP2 基因在 6 号染色体 (p21.1) 的短臂上以尾对尾的形式排列。
DOI：
10.1006/geno.1996.4513
发表时间：
1997
期刊：
Genomics.
影响因子：
--
作者：
Surguchov,A;Bronson,JD;Banerjee,P;Knowles,JA;Ruiz,C;Subbaraya,I;Palczewski,K;Baehr,W
通讯作者：
Baehr,W
鸟苷酸环化酶催化活性的测定。
影响因子：
--
作者：
Domino,SE;Tubb,DJ;Garbers,DL
通讯作者：
Garbers,DL
CFTR 的生物合成和降解。
DOI：
10.1152/physrev.1999.79.1.s167
发表时间：
1999
期刊：
Physiological reviews.
影响因子：
--
作者：
Kopito,RR
通讯作者：
Kopito,RR