Bönigk W, Altenhofen W, Müller F, Dose A, Illing M, Molday R S, Kaupp U B
Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Federal Republic of Germany.
Neuron. 1993 May;10(5):865-77. doi: 10.1016/0896-6273(93)90202-3.
Signal transduction in vertebrate rod and cone photoreceptor cells involves ion channels that are directly gated by the internal messenger cGMP. Rods and each type of cones express genetically related yet different forms of photopigments. Enzymes that control the light-stimulated hydrolysis of cGMP in rods and cones are also the product of distinct genes. Two different cDNA clones encoding cGMP-gated channels have been characterized from the chicken retina. Expression of cDNAs in Xenopus oocytes gives rise to cGMP-stimulated channel activity. Antibodies against a synthetic peptide specific for the C-terminal amino acid sequence derived from one clone stain outer segments of cone but not rod photoreceptors. Therefore chicken rod and cone cells each express different forms of cGMP-gated channels that are genetically related to each other. Expression in COS-1 cells produces the complete form of both channel polypeptides, whereas Western blot analysis indicates that channels in outer segment membranes are present in a processed form that is significantly shorter than the full-length polypeptide.
脊椎动物视杆和视锥光感受器细胞中的信号转导涉及直接由内部信使环鸟苷酸（cGMP）门控的离子通道。视杆细胞和每种类型的视锥细胞表达遗传相关但不同形式的光色素。控制视杆和视锥细胞中光刺激的cGMP水解的酶也是不同基因的产物。已从鸡视网膜中鉴定出两个编码cGMP门控通道的不同cDNA克隆。cDNA在非洲爪蟾卵母细胞中的表达产生了cGMP刺激的通道活性。针对源自一个克隆的C末端氨基酸序列的合成肽的抗体可染色视锥细胞的外段，但不染色视杆光感受器。因此，鸡的视杆细胞和视锥细胞各自表达彼此遗传相关的不同形式的cGMP门控通道。在COS-1细胞中的表达产生了两种通道多肽的完整形式，而蛋白质印迹分析表明外段膜中的通道以明显短于全长多肽的加工形式存在。
