Investigation of elements sufficient to imprint the mouse air promoter
Investigation of elements sufficient to imprint the mouse air promoter
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DOI：
10.1128/mcb.21.15.5008-5017.2001
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发表时间：
2001-08-01
影响因子：
5.3
通讯作者：
Barlow, DP
中科院分区：
文献类型：
--
作者：
Sleutels, F;Barlow, DP
小鼠胰岛素样生长因子2型受体（Igf2r）基因的印迹母体等位基因特异性表达依赖于位于该基因第二个内含子的一个3.7 kb的元件，称为2区。2区保留一个母体等位基因特异性甲基化印记，并包含一个印迹CpG岛启动子（Air），该启动子仅表达来自父本遗传等位基因的非编码反义RNA。在这里，我们使用转基因来测试Air印迹的最低要求，并测试区域2的作用是否仅限于Igf2r。以Air作为单个启动子的全长9 kb的转基因被表达，但不被印迹。当在一个44 kb的转基因上与Igf2r CPG岛启动子偶联时，Air被印迹在三条染色体中的一条上。然而，当插入腺嘌呤磷酸核糖基转移酶（Aprt）转基因的内含子时，4.6 kb片段上的Air也在14个细胞系中的2个细胞系中被印迹，并且在一个细胞系中，印迹的Air甲基化和表达已转移到Aprt CpG岛启动子上。这些数据表明，双CpG岛启动子设置可能促进作为短转基因的Air印记，也表明Air可以将印记转移到其他基因上。然而，对于可靠的Air印记，位于横跨Air-lgf2r启动子的44kb区域之外的元件是必要的。
Imprinted maternal-allele-specific expression of the mouse insulin-like growth-factor type 2 receptor (Igf2r) gene depends on a 3.7-kb element named region 2, located in the second intron of the gene. Region 2 tarries a maternal-allele-specific methylation imprint and contains an imprinted CpG island promoter (Air) that expresses a noncoding antisense RNA from the paternal inherited allele only. Here, we use transgenes to test the minimal requirements for imprinting of Air and to test if the action of region 2 is restricted to Igf2r. Transgenes up to 9 kb with Air as a single promoter are expressed but not imprinted. When coupled to the Igf2r CPG island promoter on a 44-kb transgene, Air was imprinted in one of three lines. However, Air on a 4.6-kb fragment is also imprinted in 2 of 14 lines when inserted in an intron of an adenine phosphoribosyltransferase (Aprt) transgene, and in one Une, the imprinted methylation and expression of Air have been transferred onto the Aprt CpG island promoter. These data suggest that a dual CpG island promoter setting may facilitate Air imprinting as a short transgene and also show that Air can transfer imprinting onto other genes. However, for reliable Air imprinting, elements are necessary that are located outside a 44-kb region spanning the Air-lgf2r promoters.