Cloning and functional analysis of ascidian Mitf in vivo: insights into the origin of vertebrate pigment cells
Cloning and functional analysis of ascidian Mitf in vivo: insights into the origin of vertebrate pigment cells
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DOI：
10.1016/j.mod.2003.08.009
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发表时间：
2003-12-01
影响因子：
2.6
通讯作者：
Yamamoto, H
中科院分区：
文献类型：
--
作者：
Yajima, I;Endo, K;Yamamoto, H
小眼症相关转录因子（Mitf）是一种碱性螺旋环螺旋亮氨酸拉链（bHLH-ZIP）转录因子，对脊椎动物中所有产生黑色素的色素细胞的发育和功能至关重要。为了阐明Mitf的进化历史及其与色素细胞的关联的古老性，我们分离并表征了HrMitf，Mitf-TFE bHLH-ZIP亚家族中海鞘Halocynthia roretzi的唯一成员。母体HrMirf mRNA在受精卵和从4细胞期到原肠胚期的动物半球中检测到。从神经胚到早期尾芽阶段，HrMitf优先在表达谱系特异性黑素生成基因酪氨酸酶（HrTyr）和Tyrp的色素谱系细胞中表达。HrMitf的过表达诱导间充质细胞中HrTyr酶活性的异位表达，其中HrPax 3/7的过表达诱导相同的酶活性。这表明在脊椎动物黑素细胞中观察到的Pax 3-Mitf-酪氨酸酶基因调控级联的一部分在海鞘胚胎发生期间起作用。我们还表明，HrMitf和小鼠Mitf-A，一个Mitf亚型丰富的色素上皮细胞表达，共享相似的功能特性。这些结果表明古老的Mitf-TFE亚家族与色素细胞的关联，并可能支持这样的想法，即通过祖先Mitf基因获得多个启动子（同种型）允许多种色素细胞类型的进化。(C)2003爱思唯尔爱尔兰有限公司保留所有权利。
The microphthalmia-associated transcription factor (Mitf) is a basic-helix-loop-helix-leucine zipper (bHLH-ZIP) transcription factor essential for the development and function of all melanin-producing pigment cells in vertebrates. To elucidate the evolutionary history of Mitf and the antiquity of its association with pigment cells, we have isolated and characterized HrMitf, a sole member of the Mitf-TFE bHLH-ZIP subfamily in the ascidian Halocynthia roretzi. Maternal HrMirf mRNA is detected in the fertilized egg and in the animal hemisphere from 4-cell stage through the gastrula stage. From the neurula through the early tailbud stage, HrMitf is preferentially expressed in the pigment-lineage cells that express the lineage-specific melanogenesis genes tyrosinase (HrTyr) and Tyrp. Overexpression of HrMitf induced ectopic expression of HrTyr enzyme activity in mesenchymal cells where the same enzyme activity was induced by overexpression of HrPax3/7. suggesting that a part(s) of the Pax3-Mitf-tyrosinase gene regulatory cascade seen in vertebrate melanocytes is operative during ascidian embryogenesis. We also show HrMitf and mouse Mitf-A, a Mitf isoform abundantly expressed in pigmented epithelial cells, share similar functional characteristics. These results suggest antiquity of the association of the Mitf-TFE subfamily with pigment cells and may support the idea that acquisition of multiple promoters (isoforms) by an ancestral Mitf gene has allowed the evolution of multiple pigment cell types. (C) 2003 Elsevier Ireland Ltd. All rights reserved.