IGF2R AND IGF2 GENE-EXPRESSION IN ANDROGENETIC, GYNOGENETIC, AND PARTHENOGENETIC PREIMPLANTATION MOUSE EMBRYOS - ABSENCE OF REGULATION BY GENOMIC IMPRINTING
IGF2R AND IGF2 GENE-EXPRESSION IN ANDROGENETIC, GYNOGENETIC, AND PARTHENOGENETIC PREIMPLANTATION MOUSE EMBRYOS - ABSENCE OF REGULATION BY GENOMIC IMPRINTING
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DOI：
10.1101/gad.8.3.290
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发表时间：
1994-02-01
影响因子：
10.5
通讯作者：
SCHULTZ, RM
中科院分区：
文献类型：
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作者：
LATHAM, KE;DOHERTY, AS;SCHULTZ, RM
哺乳动物的基因组印记被认为是由于配子发生过程中染色体的修饰使父本或母本等位基因失活。在胚胎和成年小鼠中，编码胰岛素样生长因子2型（Igf2）及其受体（Igf2r）的基因分别在父系和母系基因组中相互印迹和表达。我们发现这两种基因在雄激素发生、雌性发生和孤雌发生的植入前小鼠胚胎中都有表达。这些结果表明，印迹基因的失活发生在受精后（最有可能是种植后），基因组印迹和基因失活是分开的过程。我们提出，印记标记染色体，使细胞中表达的调节因子在以后的时间可以识别印记和选择性地灭活母亲或父亲的等位基因。对于这些基因，这一发现推翻了基因组印记模型，该模型要求它们从受精时起就处于非活性状态。
Genomic imprinting in mammals is believed to result from modifications to chromosomes during gametogenesis that inactivate the paternal or maternal allele. The genes encoding the insulin-like growth factor type 2 (Igf2) and its receptor (Igf2r) are reciprocally imprinted and expressed from the paternal and maternal genomes, respectively, in the fetal and adult mouse. We find that both genes are expressed in androgenetic, gynogenetic, and parthenogenetic preimplantation mouse embryos. These results indicate that inactivation of imprinted genes occurs postfertilization (most likely postimplantation) and that genomic imprinting and gene inactivation are separate processes. We propose that imprinting marks the chromosome so that regulatory factors expressed in cells at later times can recognize the imprint and selectively inactivate the maternal or paternal allele. For these genes, this finding invalidates models of genomic imprinting that require them to be inactive from the time of fertilization.