Left-right pigmentation pattern of Japanese flounder corresponds to expression levels of melanocortin receptors (MC1R and MC5R), but not to agouti signaling protein 1 (ASIP1) expression
Left-right pigmentation pattern of Japanese flounder corresponds to expression levels of melanocortin receptors (MC1R and MC5R), but not to agouti signaling protein 1 (ASIP1) expression
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DOI：
10.1016/j.ygcen.2018.03.019
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发表时间：
2018-06-01
影响因子：
2.7
通讯作者：
Tagawa, Masatomo
中科院分区：
文献类型：
--
作者：
Matsuda, Nao;Kasagi, Satoshi;Tagawa, Masatomo
比目鱼的体色是动物王国中最具特色的不对称现象之一，尽管其基本的分子机制尚不清楚。在其他硬骨鱼的背腹着色中，黑皮质素1受体（MC1R）的内源性拮抗剂agglutinalsignalingprotein1（ASIP1）的腹侧特异性表达据报道起着关键作用。ASIP1的贡献也表明在比目鱼的不对称色素沉着。为了确认ASIP 1的贡献并进一步检查受体在日本比目鱼体着色中的功能，在左侧的正常着色区域、右侧的正常非着色区域、以及右侧色素异常（表现出黑色素沉着）区域。在皮质醇刺激的黑色素沉着过度的条件下以及在黑色素沉着过度区域从无色素沉着到色素沉着的过渡期间也进行了测量。与我们的预期相反，asip1在色素沉着和非色素沉着区域的表达没有差异。在黑色素沉着区域或过渡过程中，正常和经尿道刺激的色素沉着条件之间也没有差异。相反，mc1r，mc5r和mchr2的表达水平在色素沉着区域始终较高，特别是在神经刺激条件下增加。此外，这些受体基因的表达增加之前，在未来的色素沉着的地区。我们的研究结果表明，MC1R和MC5R，但不一定ASIP1，有助于色素沉着和色素沉着症在日本比目鱼。我们提出了一个未知的分子机制，不对称的色素沉着比目鱼，是不同的，在其他脊椎动物的countershading。(C)2018爱思唯尔公司All rights reserved.
Body coloration in flatfish is one of the most distinctive asymmetries in the animal kingdom, although the fundamental molecular mechanism of the pigmentation is unclear. In the dorso-ventral coloration (countershading) of other teleost fishes, ventral-specific expression of agouti signaling protein 1 (ASIP1), an endogenous antagonist of melanocortin 1 receptor (MC1R), has been reported to play a pivotal role. Contribution of ASIP1 is also suggested in the asymmetrical pigmentation of flatfish. In order to confirm the contribution of ASIP1 and further examine receptor function in the body coloration of Japanese flounder, expression levels of asip1, mc1r, melanocortin 5 receptor (mc5r), and melanin-concentrating hormone receptor 2 (mchr2) were measured in the normally pigmented area of the left side, the normally non-pigmented area of the right side, and the abnormally pigmented (exhibiting hypermelanosis) area of the right side. Measurement was also carried out under conditions of hypermelanosis stimulated by cortisol and during the transition from non-pigmentation to pigmentation in areas of hypermelanosis. Contrary to our expectations, no difference was detected in asip1 expression between pigmented and non-pigmented areas. There was also no difference between normal and hormonally stimulated pigmented conditions in areas of hypermelanosis or during the transition process. Instead, the expression levels of mc1r, mc5r, and mchr2 were consistently higher in pigmented areas, and were especially increased under hormonally stimulated conditions. In addition, expressions of these receptor genes increased prior to pigmentation in areas of future hypermelanosis. Our results suggest that MC1Rand MC5R, but not necessarily ASIP1, contribute to pigmentation and hypermelanosis in Japanese flounder. We propose a yet unknown molecular mechanism for asymmetrical pigmentation in flatfish that is distinct from that of countershading in other vertebrates. (C) 2018 Elsevier Inc. All rights reserved.