Pittler S J, Baehr W, Wasmuth J J, McConnell D G, Champagne M S, vanTuinen P, Ledbetter D, Davis R L
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Genomics. 1990 Feb;6(2):272-83. doi: 10.1016/0888-7543(90)90567-e.
Defects in proteins that function in photoreceptor signal transduction are prime suspects as causes of some human hereditary retinal degenerations. We have characterized cDNA clones encoding the alpha-subunit of human and bovine rod cell cGMP phosphodiesterase a key phototransduction enzyme. Clones from both species contain an open reading frame capable of coding for an approximately 100-kDa polypeptide of 859 amino acids, 94% of which are identical. Two or more transcripts were detected in both human and bovine retinal poly(A)+ RNA preparations, although the human transcripts ranging from 5.3 to 4.9 kb are significantly larger than the two bovine transcripts of 4.6 and 4.0 kb. The bovine and human genes appear to exist in single copy, with the bovine gene spanning more than 140 kb of genomic DNA. Somatic cell hybrids were used to map the human gene to the long arm of chromosome 5 (5q31.2----q34). Finally, the use of the candidate gene approach in the study of hereditary retinal dystrophies is discussed.
在光感受器信号转导中发挥作用的蛋白质缺陷是导致某些人类遗传性视网膜变性的主要嫌疑因素。我们已经对编码人和牛视杆细胞cGMP磷酸二酯酶α亚基（一种关键的光转导酶）的cDNA克隆进行了表征。来自两个物种的克隆都包含一个开放阅读框，能够编码一个由859个氨基酸组成的约100 kDa的多肽，其中94%是相同的。在人和牛视网膜聚腺苷酸加尾RNA制剂中都检测到了两种或更多的转录本，尽管人源转录本范围从5.3到4.9 kb，明显大于牛源的两种转录本（4.6和4.0 kb）。牛和人的基因似乎以单拷贝形式存在，牛基因跨越超过140 kb的基因组DNA。利用体细胞杂种将人类基因定位到5号染色体长臂（5q31.2----q34）。最后，讨论了候选基因方法在遗传性视网膜营养不良研究中的应用。
