Polycomb group response elements in Drosophila and vertebrates.
Polycomb group response elements in Drosophila and vertebrates.
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DOI：
10.1016/b978-0-12-407677-8.00003-8
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发表时间：
2013
影响因子：
--
通讯作者：
Brown, J. Lesley
中科院分区：
文献类型：
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作者：
Kassis, Judith A.;Brown, J. Lesley
多梳组基因（Polycomb group genes，PcG）编码一组约16种蛋白质，这些蛋白质首先在果蝇中被鉴定为同源异型基因的阻遏物。PcG蛋白存在于所有后生动物中，并且最好表征为转录抑制物。在果蝇中，这些蛋白质被称为表观遗传调节因子，因为它们在整个发育过程中记住但不建立同源异型基因的模式化表达状态。一般来说，PcG蛋白不是DNA结合蛋白，而是以蛋白质复合物的形式抑制特定靶基因的转录。PcG蛋白如何被招募到DNA中？在果蝇中，存在称为Polycomb组反应元件（PRE）的特定调节DNA元件，其将PcG蛋白复合物带到DNA。果蝇的PRE由一系列复杂的DNA结合蛋白的结合位点组成。转基因中的功能性PRE测定已经表明，PRE在其他调控DNA的背景下起作用，并且PRE活性高度依赖于基因组背景。果蝇PRE倾向于以细胞或组织特异性的方式用复杂的调控DNA阵列调控基因，并且是调控DNA之间的相互作用决定PRE功能。在哺乳动物中，PcG蛋白更加多样化，并且有多种方式募集PcG复合物，包括RNA介导的募集。在这篇综述中，我们讨论了在脊椎动物的PREs的证据，并探讨果蝇和脊椎动物的PREs之间的异同。
Polycomb group genes (PcG) encode a group of about 16 proteins that were first identified in Drosophila as repressors of homeotic genes. PcG proteins are present in all metazoans and are best characterized as transcriptional repressors. In Drosophila, these proteins are known as epigenetic regulators because they remember, but do not establish, the patterned expression state of homeotic genes throughout development. PcG proteins, in general, are not DNA binding proteins, but act in protein complexes to repress transcription at specific target genes. How are PcG proteins recruited to the DNA? In Drosophila, there are specific regulatory DNA elements called Polycomb group response elements (PREs) that bring PcG protein complexes to the DNA. Drosophila PREs are made up of binding sites for a complex array of DNA binding proteins. Functional PRE assays in transgenes have shown that PREs act in the context of other regulatory DNA and PRE activity is highly dependent on genomic context. Drosophila PREs tend to regulate genes with a complex array of regulatory DNA in a cell or tissue-specific fashion and it is the interplay between regulatory DNA that dictates PRE function. In mammals, PcG proteins are more diverse and there are multiple ways to recruit PcG complexes, including RNA-mediated recruitment. In this review, we discuss evidence for PREs in vertebrates and explore similarities and differences between Drosophila and vertebrate PREs.