Zhang Yongqin, Liu Jinhui, Peng Liangyue, Ren Li, Zhang Huiqin, Zou Lijun, Liu Wenbin, Xiao Yamei
State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha, Hunan, 410081, China.
School of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China.
Fish Physiol Biochem. 2017 Oct;43(5):1387-1398. doi: 10.1007/s10695-017-0379-7. Epub 2017 Jul 5.
Red crucian carp (Carassius auratus red var.) is an ornamental fish with vivid red/orange color. It has been found that the adult body color of this strain forms a gray-to-red change. In this study, skin transcriptomes of red crucian carp are first obtained for three different stages of body color development, named by gray-color (GC), color-variation (CV), and red-color (RC) stages, respectively. From the skins of GC, CV, and RC, 103,229; 108,208; and 120,184 transcripts have been identified, respectively. Bioinformatics analysis reveals that 2483, 2967, and 4473 unigenes are differentially expressed between CV and GC, RC and CV, and RC and GC, respectively. A part of the differentially expressed genes (DEGs) are involved in the signaling pathway of pigment synthesis, such as the melanogenesis genes (Mitfa, Pax3a, Foxd3, Mc1r, Asip); tyrosine metabolism genes (Tyr, Dct, Tyrp1, Silva, Tat, Hpda); and pteridine metabolism genes (Gch, Xdh, Ptps, Tc). According to the data of transcriptome and quantitative PCR, the expression of Mitfa and its regulated genes which include the genes of Tyr, Tyrp1, Dct, Tfe3a, and Baxα, decreases with gray-to-red change. It is suggested that Mitfa and some genes, being related to melanin synthesis or melanophore development, are closely related to the gray-to-red body color transformation in the red crucian carp. Furthermore, the DEGs of cell apoptosis and autophagy pathway, such as Tfe3a, Baxα, Hsp70, Beclin1, Lc3, Atg9a, and Atg4a, might be involved in the melanocytes fade away of juvenile fish. These results shed light on the regulation mechanism of gray-to-red body color transformation in red crucian carp, and are helpful to the selective breeding of ornamental fish strains.
红鲫（Carassius auratus red var.）是一种具有鲜艳红/橙色的观赏鱼。已发现该品系的成鱼体色呈现从灰色到红色的变化。在本研究中，首次获得了红鲫在体色发育三个不同阶段的皮肤转录组，分别命名为灰色阶段（GC）、变色阶段（CV）和红色阶段（RC）。从GC、CV和RC的皮肤中，分别鉴定出103,229、108,208和120,184条转录本。生物信息学分析表明，CV与GC、RC与CV、RC与GC之间分别有2483、2967和4473个单基因差异表达。一部分差异表达基因（DEGs）参与色素合成信号通路，如黑色素生成基因（Mitfa、Pax3a、Foxd3、Mc1r、Asip）；酪氨酸代谢基因（Tyr、Dct、Tyrp1、Silva、Tat、Hpda）；以及蝶啶代谢基因（Gch、Xdh、Ptps、Tc）。根据转录组和定量PCR数据，Mitfa及其调控基因（包括Tyr、Tyrp1、Dct、Tfe3a和Baxα基因）的表达随从灰色到红色的变化而降低。表明Mitfa和一些与黑色素合成或黑素细胞发育相关的基因与红鲫从灰色到红色的体色转变密切相关。此外，细胞凋亡和自噬途径的差异表达基因，如Tfe3a、Baxα、Hsp70、Beclin1、Lc3、Atg9a和Atg4a，可能参与幼鱼黑素细胞的消退。这些结果揭示了红鲫从灰色到红色体色转变的调控机制，有助于观赏鱼品系的选育。
