Multiple enhancers ensure precision of gap gene-expression patterns in the Drosophila embryo
Multiple enhancers ensure precision of gap gene-expression patterns in the Drosophila embryo
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DOI：
10.1073/pnas.1109873108
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发表时间：
2011-08-16
影响因子：
11.1
通讯作者：
Levine, Michael
中科院分区：
文献类型：
--
作者：
Perry, Michael W.;Boettiger, Alistair N.;Levine, Michael
果蝇胚胎的分割始于建立空间受限的GAP基因表达模式，以响应广泛的母体转录因子的梯度，如双核生物。许多研究已经证明了这些表达模式的保真度，即使胚胎受到遗传或环境压力，但这种转录精确度的潜在机制尚不确定。在这里，我们提出的证据表明，每个GAP基因都包含多个具有重叠活性的增强子，以产生真实的基因表达模式。例如，最近发现的一种驼背(HB)增强子(位于经典增强子上游5kb)确保了前极的抑制。内含子和5‘Knirps(KNI)增强子的组合产生了忠实的表达模式，即使内含子增强子单独指导了异常广泛的表达模式。我们提出了不同的“增强子协同作用”模型，即两个具有重叠活性的增强子产生真实的基因表达模式。
Segmentation of the Drosophila embryo begins with the establishment of spatially restricted gap gene-expression patterns in response to broad gradients of maternal transcription factors, such as Bicoid. Numerous studies have documented the fidelity of these expression patterns, even when embryos are subjected to genetic or environmental stress, but the underlying mechanisms for this transcriptional precision are uncertain. Here we present evidence that every gap gene contains multiple enhancers with overlapping activities to produce authentic patterns of gene expression. For example, a recently identified hunchback (hb) enhancer (located 5-kb upstream of the classic enhancer) ensures repression at the anterior pole. The combination of intronic and 5' knirps (kni) enhancers produces a faithful expression pattern, even though the intronic enhancer alone directs an abnormally broad expression pattern. We present different models for "enhancer synergy," whereby two enhancers with overlapping activities produce authentic patterns of gene expression.