A 178-kb BAC transgene imprints the mouse Gtl2 gene and localizes tissue-specific regulatory elements.
A 178-kb BAC transgene imprints the mouse Gtl2 gene and localizes tissue-specific regulatory elements.
复制标题
178 kb BAC 转基因印记小鼠 Gtl2 基因并定位组织特异性调控元件。
DOI：
10.1016/j.ygeno.2004.04.005
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Schmidt,JenniferV
中科院分区：
文献类型：
--
作者：
Yevtodiyenko,Aleksey;Steshina,EkaterinaY;Farner,ScottC;Levorse,JohnM;Schmidt,JenniferV
基因组印记（常染色体基因的等位基因特异性表达）的调控是复杂且知之甚少的。印迹基因被组织成簇，其中顺式调控元件被认为是相互作用来控制多个基因。我们在小鼠中使用BAC转基因，开始描绘小鼠δ -like1 （Dlk1）和基因陷阱位点2 （Gtl2）印迹基因正确表达和印迹所需的DNA区域。我们证明，Gtl2基因是由BAC转基因在小鼠胚胎和胎盘中表达的，只有在母体遗传的情况下，内源性Gtl2基因也是如此。因此，Gtl2在异位染色体上正确地烙印在BAC上，并且必须携带所有必要的印记调节元件。此外，我们发现BAC Gtl2基因仅在成年动物的大脑中以接近内源性基因的水平表达，而在其他内源性表达位点（如垂体、肾上腺和骨骼肌）中则没有。这些数据将大脑Gtl2表达的增强子定位到BAC克隆中包含的DNA上，而不是其他组织的增强子。由于Dlk1基因在任何组织中都不会从BAC中表达，因此它必须需要与Gtl2表达所需的元素不同的额外元素。我们的数据细化了未来研究Gtl2印迹的间隔，并为Dlk1和Gtl2基因的不同调控提供了证据。
The regulation of genomic imprinting, the allele-specific expression of an autosomal gene, is complex and poorly understood. Imprinted genes are organized in clusters, where cis-acting regulatory elements are believed to interact to control multiple genes. We have used BAC transgenesis in the mouse to begin to delineate the region of DNA required for proper expression and imprinting of the mouse Delta-like1 (Dlk1) and Gene-trap locus2 (Gtl2) imprinted genes. We demonstrate that the Gtl2 gene is expressed from a BAC transgene in mouse embryo and placenta only upon maternal inheritance, as is the endogenous Gtl2 gene. Gtl2 is therefore properly imprinted on the BAC in an ectopic chromosomal location and must carry with it all necessary imprinting regulatory elements. Furthermore, we show that the BAC Gtl2 gene is expressed at levels approaching those of the endogenous gene only in the brain of adult animals, not in other sites of endogenous expression such as the pituitary, adrenal, and skeletal muscle. These data localize the enhancer(s) for brain Gtl2 expression, but not those for other tissues, to the DNA contained within the BAC clone. As the Dlk1 gene is not expressed from the BAC in any tissues, it must require additional elements that are different from those necessary for Gtl2 expression. Our data refine the interval for future investigation of Gtl2 imprinting and provide evidence for distinct regulation of the linked Dlk1 and Gtl2 genes.