Origin and evolution of retinoid isomerization machinery in vertebrate visual cycle: hint from jawless vertebrates.
Origin and evolution of retinoid isomerization machinery in vertebrate visual cycle: hint from jawless vertebrates.
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DOI：
10.1371/journal.pone.0049975
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Redmond TM
中科院分区：
文献类型：
--
作者：
Poliakov E;Gubin AN;Stearn O;Li Y;Campos MM;Gentleman S;Rogozin IB;Redmond TM
为了在所有光线水平下保持视觉敏感性，脊椎动物的眼睛具有在黑暗中酶促再生视觉色素发色团11顺式视网膜的机制，而不同于所有其他依赖光异构化的分类群。这种机制被称为视觉周期，定位于视网膜色素上皮(RPE)，这是神经视网膜的支撑层。长期以来，人们的猜测一直围绕着更原始的脊索动物，如被囊动物和头索动物，是否预见到了这一特征。视觉周期的两个关键酶是RPE65和卵磷脂：视黄醇酰基转移酶(LRAT)，RPE65是视觉周期中的全反式视黄酸酯水解酶，而卵磷脂：视黄醇酰基转移酶产生RPE65‘S底物。我们假设，脊椎动物视觉周期的起源直接与祖先的类胡萝卜素加氧酶有关，该加氧酶获得了一种新的视黄酸酯异位水解酶功能。我们对RPE65/BCMO和N1pC/P60(LRAT)超家族的系统发育分析表明，RPE65和LRAT同源物都不存在于被毛类(Ciona)或头颈类动物(Branchiostoma)中，而存在于无颌脊椎动物Petromyzon marinus(Sea Lamprey)中。在Ciona和Branchiostoma中与RPE65最接近的同源物在所有正品RPE65中都缺乏预测的功能分歧残基，但七鳗鱼RPE65中包含所有这些残基。我们从七鳃鳗RPE中克隆了RPE65和LRATb的cDNAs，并显示了适当的酶活性。我们发现乔纳-胡萝卜素单加氧酶a(BCMOa)(以前被注释为RPE65)具有类胡萝卜素加氧酶切割活性，但不具有RPE65活性。我们通过免疫荧光显微镜、免疫印迹和质谱仪验证了七鳃鳗RPE中RPE65的存在。在这些数据的基础上，我们得出结论，从典型的类胡萝卜素双键断裂功能(BCMO)到异构体水解酶功能(RPE65)的关键转变，加上LRAT的起源，发生在更原始的脊索动物(被囊类等)分化之后。在无颌和有颌脊椎动物的最后一个共同祖先中。
In order to maintain visual sensitivity at all light levels, the vertebrate eye possesses a mechanism to regenerate the visual pigment chromophore 11-cis retinal in the dark enzymatically, unlike in all other taxa, which rely on photoisomerization. This mechanism is termed the visual cycle and is localized to the retinal pigment epithelium (RPE), a support layer of the neural retina. Speculation has long revolved around whether more primitive chordates, such as tunicates and cephalochordates, anticipated this feature. The two key enzymes of the visual cycle are RPE65, the visual cycle all-trans retinyl ester isomerohydrolase, and lecithin:retinol acyltransferase (LRAT), which generates RPE65’s substrate. We hypothesized that the origin of the vertebrate visual cycle is directly connected to an ancestral carotenoid oxygenase acquiring a new retinyl ester isomerohydrolase function. Our phylogenetic analyses of the RPE65/BCMO and N1pC/P60 (LRAT) superfamilies show that neither RPE65 nor LRAT orthologs occur in tunicates (Ciona) or cephalochordates (Branchiostoma), but occur in Petromyzon marinus (Sea Lamprey), a jawless vertebrate. The closest homologs to RPE65 in Ciona and Branchiostoma lacked predicted functionally diverged residues found in all authentic RPE65s, but lamprey RPE65 contained all of them. We cloned RPE65 and LRATb cDNAs from lamprey RPE and demonstrated appropriate enzymatic activities. We show that Ciona ß-carotene monooxygenase a (BCMOa) (previously annotated as an RPE65) has carotenoid oxygenase cleavage activity but not RPE65 activity. We verified the presence of RPE65 in lamprey RPE by immunofluorescence microscopy, immunoblot and mass spectrometry. On the basis of these data we conclude that the crucial transition from the typical carotenoid double bond cleavage functionality (BCMO) to the isomerohydrolase functionality (RPE65), coupled with the origin of LRAT, occurred subsequent to divergence of the more primitive chordates (tunicates, etc.) in the last common ancestor of the jawless and jawed vertebrates.
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影响因子：
4.8
作者：
Batten, ML;Imanishi, Y;Palczewski, K
通讯作者：
Palczewski, K
影响因子：
5.8
作者：
Arnold, K;Bordoli, L;Schwede, T
通讯作者：
Schwede, T
影响因子：
2.9
作者：
Gollapalli, DR;Rando, RR
通讯作者：
Rando, RR
影响因子：
12.3
作者：
Kondrashov FA;Rogozin IB;Wolf YI;Koonin EV
通讯作者：
Koonin EV
DOI：
10.1073/pnas.1010350107
发表时间：
2010-11-09
影响因子：
11.1
作者：
Heimberg, Alysha M.;Cowper-Sallari, Richard;Peterson, Kevin J.
通讯作者：
Peterson, Kevin J.