Wang Xueping, Liu Yalan, Chen Hongsheng, Mei Lingyun, He Chufeng, Jiang Lu, Niu Zhijie, Sun Jie, Luo Hunjin, Li Jiada, Feng Yong
Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
Province Key Laboratory of Otolaryngology Critical Disease, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
PLoS One. 2015 Nov 18;10(11):e0143142. doi: 10.1371/journal.pone.0143142. eCollection 2015.
TYR, DCT and MITF are three important genes involved in maintaining the mature phenotype and producing melanin; they therefore participate in neural crest cell development into melanocytes. Previous studies have revealed that the Wnt signaling factor lymphoid enhancer-binding factor (LEF-1) can enhance DCT and MITF gene expression. However, whether LEF-1 also affects TYR gene expression remains unclear. In the present study, we found that LEF-1 regulated TYR transcription in vitro. LEF-1 overexpression increased TYR gene promoter activity, whereas LEF-1 knockdown by RNA interference significantly decreased TYR expression. Moreover, the core GTTTGAT sequence (-56 to -50) within the TYR promoter is essential for the effect of LEF-1 on TYR expression, and chromatin immunoprecipitation (ChIP) assay indicated that endogenous LEF-1 interacts with the TYR promoter. In addition, we observed a synergistic transactivation of the TYR promoter by LEF-1 and MITF. These data suggest that Wnt signaling plays an important role in regulating melanocyte development and differentiation.
酪氨酸酶（TYR）、二羟基吲哚羧酸（DCT）和小眼畸形相关转录因子（MITF）是参与维持成熟表型和产生黑色素的三个重要基因；因此，它们参与神经嵴细胞向黑素细胞的发育过程。先前的研究表明，Wnt信号因子淋巴细胞增强因子结合因子1（LEF-1）可增强DCT和MITF基因的表达。然而，LEF-1是否也影响TYR基因的表达仍不清楚。在本研究中，我们发现LEF-1在体外调节TYR的转录。LEF-1的过表达增加了TYR基因启动子的活性，而通过RNA干扰敲低LEF-1则显著降低了TYR的表达。此外，TYR启动子内的核心GTTTGAT序列（-56至-50）对于LEF-1对TYR表达的影响至关重要，染色质免疫沉淀（ChIP）分析表明内源性LEF-1与TYR启动子相互作用。此外，我们观察到LEF-1和MITF对TYR启动子具有协同反式激活作用。这些数据表明，Wnt信号在调节黑素细胞的发育和分化中起重要作用。
