Performance of genomic bordering elements at predefined genomic loci
Performance of genomic bordering elements at predefined genomic loci
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DOI：
10.1128/mcb.25.6.2260-2272.2005
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发表时间：
2005-03-01
影响因子：
5.3
通讯作者：
Bode, J
中科院分区：
文献类型：
--
作者：
Goetze, S;Baer, A;Bode, J
真核DNA被组织成染色质结构域，其调节基因表达和染色体行为。绝缘子和/或支架-基质附着区（S/MAR）标记这些染色质结构域的边界，在那里它们从外部界定增强和沉默效应。通过重组酶介导的盒交换（RMCE），我们能够比较这两种类型的边界元件在一些预定义的基因组位点。侧翼的表达载体与S/MAR或两个拷贝的非S/MAR鸡过敏性位点4绝缘子表明，虽然这些边界赋予相关的表达特性，在大多数位点，它们对染色质组织的影响是明显不同的。我们的研究结果表明，边界元素的活动是最明显的丰富类的基因座与低，但可以忽略不计的表达潜力的情况下，高表达的网站。通过RMCE程序，我们证明了表达参数不是由于边界元件的潜在靶向作用，在这个意义上说，一个连接的转基因是针对一类特殊的基因座。相反，我们可以将观察到的转录增强现象与它们作为基因组绝缘体的功能联系起来。
Eukaryotic DNA is organized into chromatin domains that regulate gene expression and chromosome behavior. Insulators and/or scaffold-matrix attachment regions (S/MARs) mark the boundaries of these chromatin domains where they delimit enhancing and silencing effects from the outside. By recombinase-mediated cassette exchange (RMCE), we were able to compare these two types of bordering elements at a number of predefined genomic loci. Flanking an expression vector with either S/MARs or two copies of the non-S/MAR chicken hypersensitive site 4 insulator demonstrates that while these borders confer related expression characteristics at most loci, their effect on chromatin organization is clearly distinct. Our results suggest that the activity of bordering elements is most pronounced for the abundant class of loci with a low but negligible expression potential in the case of highly expressed sites. By the RMCE procedure, we demonstrate that expression parameters are not due to a potential targeting action of bordering elements, in the sense that a linked transgene is directed into a special class of loci. Instead, we can relate the observed transcriptional augmentation phenomena to) their function as genomic insulators.