BACKGROUND & AIMS:
:Neural crest cells form diverse derivatives that vary according to their level of origin along the body axis, with only cranial neural crest cells contributing to facial skeleton. Interestingly, the transcription factor Ets-1 is uniquely expressed in cranial but not trunk neural crest, where it functions as a direct input into neural crest specifier genes, Sox10 and FoxD3. We have isolated and interrogated a cis-regulatory element, conserved between birds and mammals, that drives reporter expression in a manner that recapitulates that of endogenous Ets-1 expression in the neural crest. Within a minimal Ets-1 enhancer region, mutation of putative binding sites for SoxE, homeobox, Ets, TFAP2 or Fox proteins results in loss or reduction of neural crest enhancer activity. Morpholino-mediated loss-of-function experiments show that Sox9, Pax7, Msx1/2, Ets-1, TFAP2A and FoxD3, all are required for enhancer activity. In contrast, mutation of a putative cMyc/E-box sequence augments reporter expression, consistent with this being a repressor binding site. Taken together, these results uncover new inputs into Ets-1, revealing critical links in the cranial neural crest gene regulatory network.
背景与目标:
神经c细胞形成各种衍生物,这些衍生物根据它们沿体轴的起源水平而变化,只有颅神经neural细胞有助于面部骨骼。有趣的是,转录因子Ets-1在颅骨中独特表达,但在躯干神经not中却不表达,在这里它直接充当神经rest指定基因Sox10和FoxD3的输入。我们已经分离并审视了鸟类和哺乳动物之间保守的顺式调控元件,该元件以一种可以报道神经of中内源性Ets-1表达的方式驱动报告基因表达。在最小的Ets-1增强子区域内,SoxE,同源盒,Ets,TFAP2或Fox蛋白的假定结合位点发生突变会导致神经rest增强子活性丧失或降低。 Morpholino介导的功能丧失实验表明,Sox9,Pax7,Msx1 / 2,Ets-1,TFAP2A和FoxD3都是增强子活性所必需的。相反,推定的cMyc / E-box序列的突变会增加报告基因的表达,这与阻遏物结合位点一致。综上所述,这些结果揭示了Ets-1的新输入,揭示了颅神经c基因调控网络中的关键环节。