A dual role for DNA binding by Runt in activation and repression of sloppy paired transcription.
A dual role for DNA binding by Runt in activation and repression of sloppy paired transcription.
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DOI：
10.1091/mbc.e20-08-0509
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发表时间：
2021-11-01
影响因子：
3.3
通讯作者：
Gergen JP
中科院分区：
文献类型：
--
作者：
Prazak L;Iwasaki Y;Kim AR;Kozlov K;King K;Gergen JP
这项工作调查的作用，由Runt的DNA结合在调节草率配对1（slp1）基因，特别是两个不同的顺式调节元件，介导调节由Runt和其他配对规则的转录因子在果蝇分割。我们发现，一个DNA结合缺陷形式的Runt是无效的阻遏远端（DESE）和近端（PESE）的slp1的早期条纹元素，也受到损害的DESE依赖性激活。使用位点特异性转基因和定量成像技术进一步研究DESE中Runt结合位点的功能。当DESE作为自主增强子进行测试时，Runt位点的诱变导致Runt依赖性抑制的明显丧失，但对Runt依赖性激活几乎没有影响。值得注意的是，在还含有PESE增强子的报告基因构建体的背景下，这些相同位点的诱变导致DESE依赖性激活的显著降低以及对于自主突变型DESE增强子观察到的阻遏的丧失。这些结果提供了强有力的证据，证明Runt的DNA结合直接有助于这两个增强子在早期胚胎中相互作用的调节相互作用。
This work investigates the role of DNA binding by Runt in regulating the sloppy paired 1 (slp1) gene and in particular two distinct cis-regulatory elements that mediate regulation by Runt and other pair-rule transcription factors during Drosophila segmentation. We find that a DNA-binding–defective form of Runt is ineffective at repressing both the distal (DESE) and proximal (PESE) early stripe elements of slp1 and is also compromised for DESE-dependent activation. The function of Runt-binding sites in DESE is further investigated using site-specific transgenesis and quantitative imaging techniques. When DESE is tested as an autonomous enhancer, mutagenesis of the Runt sites results in a clear loss of Runt-dependent repression but has little to no effect on Runt-dependent activation. Notably, mutagenesis of these same sites in the context of a reporter gene construct that also contains the PESE enhancer results in a significant reduction of DESE-dependent activation as well as the loss of repression observed for the autonomous mutant DESE enhancer. These results provide strong evidence that DNA binding by Runt directly contributes to the regulatory interplay of interactions between these two enhancers in the early embryo.