Mizusawa Kanta, Kawashima Yusuke, Sunuma Toshikazu, Hamamoto Akie, Kobayashi Yuki, Kodera Yoshio, Saito Yumiko, Takahashi Akiyoshi
School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan.
School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0373, Japan.
Gen Comp Endocrinol. 2015 Apr 1;214:140-8. doi: 10.1016/j.ygcen.2014.07.008. Epub 2014 Jul 21.
In teleosts, melanin-concentrating hormone (MCH) plays a key role in skin color changes. MCH is released into general circulation from the neurohypophysis, which causes pigment aggregation in the skin chromatophores. Recently, a novel MCH (MCH2) precursor gene, which is orthologous to the mammalian MCH precursor gene, has been identified in some teleosts using genomic data mining. The physiological function of MCH2 remains unclear. In the present study, we cloned the cDNA for MCH2 from barfin flounder, Verasper moseri. The putative prepro-MCH2 contains 25 amino acids of MCH2 peptide region. Liquid chromatography-electrospray ionization mass spectrometry with a high resolution mass analyzer were used for confirming the amino acid sequences of MCH1 and MCH2 peptides from the pituitary extract. In vitro synthesized MCH1 and MCH2 induced pigment aggregation in a dose-dependent manner. A mammalian cell-based assay indicated that both MCH1 and MCH2 functionally interacted with both the MCH receptor types 1 and 2. Mch1 and mch2 are exclusively expressed in the brain and pituitary. The levels of brain mch2 transcript were three times higher in the fish that were chronically acclimated to a white background than those acclimated to a black background. These results suggest that in V. moseri, MCH1 and MCH2 are involved in the response to changes in background colors, during the process of chromatophore control.
在硬骨鱼中，黑色素浓缩激素（MCH）在皮肤颜色变化中起关键作用。MCH从神经垂体释放到体循环中，导致皮肤色素细胞中的色素聚集。最近，通过基因组数据挖掘在一些硬骨鱼中鉴定出了一种与哺乳动物MCH前体基因同源的新型MCH（MCH2）前体基因。MCH2的生理功能仍不清楚。在本研究中，我们从条石鲷（Verasper moseri）中克隆了MCH2的cDNA。推测的前体MCH2包含25个氨基酸的MCH2肽区域。使用配备高分辨率质量分析仪的液相色谱 - 电喷雾电离质谱法来确认垂体提取物中MCH1和MCH2肽的氨基酸序列。体外合成的MCH1和MCH2以剂量依赖性方式诱导色素聚集。基于哺乳动物细胞的试验表明，MCH1和MCH2在功能上均与MCH受体1型和2型相互作用。Mch1和mch2仅在脑和垂体中表达。长期适应白色背景的鱼脑中mch2转录本水平比适应黑色背景的鱼高三倍。这些结果表明，在条石鲷中，MCH1和MCH2在色素细胞控制过程中参与对背景颜色变化的反应。
