Nabetani A, Hatada I, Morisaki H, Oshimura M, Mukai T
Department of Bioscience, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
Mol Cell Biol. 1997 Feb;17(2):789-98. doi: 10.1128/MCB.17.2.789.
The mouse U2af1-rs1 gene is an endogenous imprinted gene on the proximal region of chromosome 11. This gene is transcribed exclusively from the unmethylated paternal allele, while the methylated maternal allele is silent. An analysis of genome structure of this gene revealed that the whole gene is located in an intron of the Murr1 gene. Although none of the three human U2af1-related genes have been mapped to chromosome 2, the human homolog of Murr1 is assigned to chromosome 2. The mouse Murr1 gene is transcribed biallelically, and therefore it is not imprinted in neonatal mice. Allele-specific methylation is limited to a region around U2af1-rs1 in an intron of Murr1. These results suggest that in chromosomal homology and genomic imprinting, the U2af1-rs1 gene is distinct from the genome region surrounding it. We have proposed the neomorphic origin of the U2af1-rs1 gene by retrotransposition and the particular mechanism of genomic imprinting of ectopic genes.
小鼠U2af1-rs1基因是位于11号染色体近端区域的一个内源性印记基因。该基因仅从未甲基化的父本等位基因转录，而甲基化的母本等位基因则保持沉默。对该基因的基因组结构分析表明，整个基因位于Murr1基因的一个内含子中。尽管人类的三个U2af1相关基因均未定位到2号染色体上，但Murr1的人类同源基因被定位于2号染色体。小鼠Murr1基因以双等位基因方式转录，因此在新生小鼠中不具有印记。等位基因特异性甲基化仅限于Murr1内含子中U2af1-rs1周围的区域。这些结果表明，在染色体同源性和基因组印记方面，U2af1-rs1基因与其周围的基因组区域不同。我们通过逆转座提出了U2af1-rs1基因的新功能起源以及异位基因基因组印记的特殊机制。
