Commonwealth Scientific and Industrial Research Organisation (CSIRO) Food Futures Flagship, Division of Marine and Atmospheric Research, Ecosciences Precinct, Dutton Park, QLD 4102, Australia.
J Exp Biol. 2012 Jan 15;215(Pt 2):343-50. doi: 10.1242/jeb.064592.
Exposure of prawns to dark- or light-coloured substrates is known to trigger a strong colour adaptation response through expansion or contraction of the colouration structures in the prawn hypodermis. Despite the difference in colour triggered by this adaptive response, total levels of the predominant carotenoid pigment, astaxanthin, are not modified, suggesting that another mechanism is regulating this phenomenon. Astaxanthin binds to a specific protein called crustacyanin (CRCN), and it is the interaction between the quantities of each of these compounds that produces the diverse range of colours seen in crustacean shells. In this study, we investigated the protein changes and genetic regulatory processes that occur in prawn hypodermal tissues during adaptation to black or white substrates. The amount of free astaxanthin was higher in animals adapted to dark substrate compared with those adapted to light substrate, and this difference was matched by a strong elevation of CRCN protein. However, there was no difference in the expression of CRCN genes either across the moult cycle or in response to background substrate colour. These results indicate that exposure to a dark-coloured substrate causes an accumulation of CRCN protein, bound with free astaxanthin, in the prawn hypodermis without modification of CRCN gene expression. On light-coloured substrates, levels of CRCN protein in the hypodermis are reduced, but the carotenoid is retained, undispersed in the hypodermal tissue, in an esterified form. Therefore, the abundance of CRCN protein affects the distribution of pigment in prawn hypodermal tissues, and is a crucial regulator of the colour adaptation response in prawns.
对虾暴露在深色或浅色基质中会引发强烈的颜色适应反应，通过虾皮下组织中颜色结构的扩张或收缩来实现。尽管这种适应性反应所触发的颜色不同，但主要类胡萝卜素色素虾青素的总水平没有改变，这表明另一种机制在调节这种现象。虾青素与一种叫做甲壳蓝蛋白（CRCN）的特定蛋白质结合，正是这些化合物的数量之间的相互作用产生了甲壳类动物壳中所见的多种颜色。在这项研究中，我们研究了虾皮下组织在适应黑色或白色基质过程中发生的蛋白质变化和遗传调节过程。与适应浅色基质的动物相比，适应深色基质的动物中游离虾青素的含量更高，而 CRCN 蛋白的强烈升高与这种差异相匹配。然而，无论是在蜕皮周期内还是对背景基质颜色的反应中，CRCN 基因的表达都没有差异。这些结果表明，暴露在深色基质中会导致虾皮下组织中 CRCN 蛋白与游离虾青素结合的积累，而不会改变 CRCN 基因的表达。在浅色基质上，虾皮下组织中 CRCN 蛋白的水平降低，但类胡萝卜素以酯化形式保留在虾皮下组织中，未分散。因此，CRCN 蛋白的丰度影响虾皮下组织中色素的分布，是虾类颜色适应反应的关键调节剂。
