cDNA, gene structure, and chromosomal localization of human GAR1 (CNCG3L), a homolog of the third subunit of bovine photoreceptor cGMP-gated channel.
cDNA, gene structure, and chromosomal localization of human GAR1 (CNCG3L), a homolog of the third subunit of bovine photoreceptor cGMP-gated channel.
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人 GAR1 (CNCG3L) 的 cDNA、基因结构和染色体定位，GAR1 是牛感光器 cGMP 门控通道第三个亚基的同源物。
DOI：
10.1006/geno.1995.1102
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Pittler,SJ
中科院分区：
文献类型：
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作者：
Ardell,MD;Makhija,AK;Oliveira,L;Miniou,P;Viegas-Pequignot,E;Pittler,SJ
先前在牛视杆光感受器中鉴定出独特的富含谷氨酸的蛋白质（Sugimoto等人，1991，Proc.Natl. Acad. Sci. USA 88：3116-31191），后来被认为是视杆cGMP门控阳离子通道的第三亚基（γ）（Chen等人，1994，Proc.Natl. Acad. Sci. USA 91：11757-117611.在这里，我们报告的GAR 1基因编码的牛γ的人类同源物的表征。编码人γ的cDNA克隆的序列分析揭示了一个开放阅读框架，预测了一个299个氨基酸（约32 kDa）的蛋白质，其大小是牛γ亚基的一半。牛γ的N-末端半部分与预测的人γ序列的比较显示，前31个氨基酸内的同源性为90%，在蛋白质序列的其余部分中仅发现60%的同源性。与牛γ蛋白一样，尽管不存在牛C-末端富含谷氨酸的结构域，但人蛋白的预测等电点非常酸性。通过分析跨越GAR 1基因的几个重叠基因组克隆，证实了cDNA序列的完整性。该基因的蛋白质编码区由12个外显子组成，全长约11 kb，外显子序列与cDNA克隆的外显子序列相同。用扩增GAR 1基因（基因座命名为CNCG 3L）的一部分的引物对对体细胞杂交DNA进行PCR，证明其定位于染色体16。通过荧光原位杂交将该基因定位在16 q13，进一步限定了该基因的位置。在同一区域内，先前报道了与Bardet-Biedl syadrome的连锁，这是一种涉及视网膜变性的疾病，表明GAR 1是这种疾病的良好候选基因。
A unique glutamic acid-rich protein was previously identified in bovine rod photoreceptors (Sugimoto et al., 1991, Proc. Natl. Acad. Sci. USA 88:3116-31191) and later suggested to be a third subunit (γ) of the rod cGMP-gated cation channel (Chen et al., 1994, Proc. Natl. Acad. Sci. USA 91:11757-117611. Here, we report on the characterization of the GAR1 gene encoding a human homolog of bovine γ. Sequence analysis of cDNA clones encoding human γ revealed an open reading frame predicting a protein of 299 amino acids (∼32 kDa), half the size of the bovine γ subunit. Comparison of the N-terminal half of bovine γ with the predicted human γ sequence revealed 90% identity within the first 31 amino acids, and only 60% homology was found throughout the remainder of the protein sequence. As in bovine γ, the predicted isoelectric point of the human protein is very acidic despite the absence of the bovine C-terminal glutamic acid-rich domain. The integrity of the cDNA sequence was confirmed by analysis of several overlapping genomic clones that span the GAR1 gene. The protein coding region of the gene consists of 12 exons spanning ∼11 kb with exon sequence identical to that of the cDNA clones. PCR of somatic cell hybrid DNA with primer pairs that amplify a portion of the GAR1 gene (locus designation CNCG3L) demonstrate localization, to chromosome 16. The location of the gene was further delimited by fluorescence in situ hybridization placing the gene at 16q13. Within this same region linkage was previously reported with Bardet-Biedl syadrome, a disease involving retinal degeneration, suggesting that GAR1 is a good candidate gene for this disorder.