Transcription of fgf8 is regulated by activating and repressive cis-elements at the midbrain-hindbrain boundary in zebrafish embryos
Transcription of fgf8 is regulated by activating and repressive cis-elements at the midbrain-hindbrain boundary in zebrafish embryos
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DOI：
10.1016/j.ydbio.2008.01.013
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发表时间：
2008-04-15
影响因子：
2.7
通讯作者：
Yamasu, Kyo
中科院分区：
文献类型：
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作者：
Inoue, Fumitaka;Parvin, Mst. Shahnaj;Yamasu, Kyo
Fgf8在发育中的大脑峡区表达，在脊椎动物胚胎中起组织功能。我们之前发现斑马鱼fgf8基因下游的S4.2是一个驱动前后脑转录的调控区域。在这里，我们研究了发育过程中S4.2区域调控fgf8的机制。胚胎报告分析显示，S4.2密切再现了体细胞发生过程中fgf8在前脑和后脑的表达。该区域包含一个在多种脊椎动物fgf8中高度保守的序列。S4.2的进一步分析显示，一个342 bp的核心区由3个亚区（#2、#3和#4）组成。区域#3和#4在大脑中从中脑到后脑r5广泛地驱动表达，而#2的28 bp序列抑制中脑和r2到r5的异位表达。在pax2a突变胚胎中，S4.2的增强子功能缺失，而由于pax2a在后脑中的错表达，S4.2的增强子功能被异位激活。我们在体外和体内鉴定了两个与Pax2a结合的核心区域位点，其破坏使S4.2活性丧失。因此，fgf8在前脑和后脑的表达涉及激活和抑制，Pax2a是一个关键的调节因子。(C) 2008爱思唯尔公司版权所有。
Fgf8 is expressed in the isthmic region of the developing brain, serving an organizing function in vertebrate embryos. We previously identified S4.2 downstream to the zebrafish fgf8 gene as a regulatory region that drives transcription in the anterior hindbrain. Here, we investigated the mechanism of fgf8 regulation by the S4.2 region during development. Reporter analyses in embryos revealed that S4.2 closely recapitulates fgf8 expression in the anteriormost hindbrain during somitogenesis. This region contains a sequence highly conserved in fgf8 of diverse vertebrates. Further analyses of S4.2 revealed a 342-bp core region composed of three subregions (#2, #3, and #4). Regions #3 and #4 drove expression broadly in the brain from the midbrain to r5 of the hindbrain, whereas a 28-bp sequence in #2 repressed ectopic expression in the midbrain and in r2 to r5. The enhancer function of S4.2 was absent in pax2a mutant embryos, while it was activated ectopically by pax2a misexpression in the hindbrain. We identified two sites in the core region that are bound by Pax2a in vitro and in vivo, the disruption of which abrogated the S4.2 activity. Thus,fgf8 expression in the anteriormost hindbrain involves activation and repression, with Pax2a as a pivotal regulator. (C) 2008 Elsevier Inc. All rights reserved.