UASrpg can function as a heterochromatin boundary element in yeast
UASrpg can function as a heterochromatin boundary element in yeast
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DOI：
10.1101/gad.13.9.1089
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发表时间：
1999-05-01
影响因子：
10.5
通讯作者：
Broach, JR
中科院分区：
文献类型：
--
作者：
Bi, X;Broach, JR
酿酒酵母中的HM基因座构成了区域特异性但基因非特异性的抑制结构域，因为当放置在这些基因座上时，许多由RNA聚合酶II或III转录的外源基因被沉默。然而，在酵母中，棉蚜TEF基因启动子和酿酒酵母的TEM和TEF2基因对HM沉默子的转录沉默具有抗性。此外，当插入HML α基因和E沉默子之间时，这些启动子的某些片段阻断了沉默子对α基因的抑制作用。所有这些片段都含有由Rap1的多个结合位点组成的UAS(rpg)（核糖体蛋白基因上游激活序列）。事实上，酵母TEF2的UAS（rpg）中一个149 bp的片段仅由三个串联rap1结合位点组成，具有沉默阻断活性。该元件还具有已知染色质边界元件的绝缘活性和取向依赖特性。最后，该元件阻断了异染色质在消声器处的物理扩散。本节提供了酵母中染色质结构域边界或绝缘体元件的第一个例子。
The HM loci in Saccharomyces cerevisiae constitute region-specific but gene-nonspecific repression domains, as a number of heterologous genes transcribed by RNA polymerase II or III are silenced when placed at these loci. The promoters of the Ashbya gossypii TEF gene and the S. cerevisiae TEM and TEF2 genes, however, are resistant to transcriptional silencing by the HM silencers in yeast. Moreover, when interposed between the HML alpha genes and the E silencer, certain segments of these promoters block the repression effect of the silencer on the alpha genes. All of these fragments contain UAS(rpg) (upstream activation sequence of ribosome protein genes) composed of multiple binding sites for Rap1. In fact, a 149-bp segment consisting essentially of only three tandem Rap1-binding sites from the UAS(rpg) of yeast TEF2 exhibits silencer-blocking activity. This element also exhibits insulating activity and orientation dependence characteristic of known chromatin boundary elements. finally, the element blocks the physical spread of heterochromatin initiated at a silencer. This segment provides the first example of chromatin domain boundary or insulator elements in yeast.