A Visual Pigment Expressed in Both Rod and Cone Photoreceptors

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• 作者：Jian-xing Ma ; Sergey Znoiko ; Kashelle L. Othersen ; James C. Ryan ; Joydip Das ; Tomoki Isayama ; Masahiro Kono ; Daniel D. Oprian ; D. Wesley Corson ; M. Carter Cornwall et al.
• 刊名：Neuron
• 出版年：2001
• 出版时间：8 November 2001
• 年：2001
• 卷：32
• 期：3
• 页码：451-461
• 全文大小：1079 K

文摘

Rods and cones contain closely related but distinct G protein-coupled receptors, opsins, which have diverged to meet the differing requirements of night and day vision. Here, we provide evidence for an exception to that rule. Results from immunohistochemistry, spectrophotometry, and single-cell RT-PCR demonstrate that, in the tiger salamander, the green rods and blue-sensitive cones contain the same opsin. In contrast, the two cells express distinct G protein transducin α subunits: rod α transducin in green rods and cone α transducin in blue-sensitive cones. The different transducins do not appear to markedly affect photon sensitivity or response kinetics in the green rod and blue-sensitive cone. This suggests that neither the cell topology or the transducin is sufficient to differentiate the rod and the cone response.