Du Minjie, Beatty Linda G, Zhou Wenjing, Lew Jocelyne, Schoenherr Christopher, Weksberg Rosanna, Sadowski Paul D
Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
Hum Mol Genet. 2003 Aug 1;12(15):1927-39. doi: 10.1093/hmg/ddg194.
The imprinting of the genes on human chromosome 11p15.5 is thought to be controlled by two imprinting control regions located in two differentially methylated CpG islands upstream of the H19 gene (H19 DMR) and in intron 10 of the KCNQ1 gene (KvDMR). We have examined sequences in the human 11p15.5 genomic imprinted region for the presence of insulators and silencers using a position- and enhancer-dependent stable transfection assay. We have confirmed the existence of insulators in H19 DMR and discovered two novel insulators in the IGF2 gene. We have also found two novel silencer sequences; one is located in KvDMR, a region that is thought to contain the promoter for the KCNQ1OT1 transcript, and another is in the CDKN1C gene. We have demonstrated binding of CTCF protein in vitro to all the insulator and silencer sequences that we have detected. We discuss the differences in the regulation of imprinting controlled by the two imprinting control regions in chromosome 11p.
人们认为，人类染色体11p15.5上基因的印记是由两个印记控制区域调控的，这两个区域分别位于H19基因上游两个差异甲基化的CpG岛（H19 DMR）以及KCNQ1基因的内含子10（KvDMR）中。我们使用一种依赖于位置和增强子的稳定转染试验，检测了人类11p15.5基因组印记区域中是否存在绝缘子和沉默子序列。我们证实了H19 DMR中存在绝缘子，并在IGF2基因中发现了两个新的绝缘子。我们还发现了两个新的沉默子序列；一个位于KvDMR，该区域被认为包含KCNQ1OT1转录本的启动子，另一个位于CDKN1C基因中。我们已经证明，CTCF蛋白在体外与我们检测到的所有绝缘子和沉默子序列结合。我们讨论了11号染色体上两个印记控制区域对印记调控的差异。
