Zemel S, Bartolomei M S, Tilghman S M
Howard Hughes Medical Institute, Princeton University, New Jersey 08544.
Nat Genet. 1992 Sep;2(1):61-5. doi: 10.1038/ng0992-61.
Parental imprinting is a phenomenon in mammals whereby the maternal and paternal alleles of a gene are differentially expressed. Three murine genes have been shown to display this type of allele-specific expression. Two of them, insulin-like growth factor-2 (Igf-2) and H19, map to the distal end of mouse chromosome 7, but are imprinted in opposite directions. Pulsed-field gel electrophoresis and large-fragment DNA cloning were utilized to establish a physical map that includes H19 and Igf-2. Igf-2 lies approximately 90 kilobases of DNA 5' to H19, in the same transcriptional orientation. This physical proximity is conserved in humans, based on pulsed-field gel analysis. We conclude that H19 and Igf-2 constitute an imprinted domain.
亲本印记是哺乳动物中的一种现象，即基因的母本和父本等位基因会有差异地表达。已证明三种小鼠基因表现出这种等位基因特异性表达。其中两个基因，胰岛素样生长因子2（Igf-2）和H19，定位于小鼠7号染色体的远端，但印记方向相反。利用脉冲场凝胶电泳和大片段DNA克隆技术建立了一个包含H19和Igf-2的物理图谱。Igf-2位于H19上游约90千碱基对处，转录方向相同。基于脉冲场凝胶分析，这种物理上的邻近性在人类中是保守的。我们得出结论，H19和Igf-2构成一个印记结构域。
