Meguro M, Mitsuya K, Sui H, Shigenami K, Kugoh H, Nakao M, Oshimura M
Department of Molecular and Cell Genetics, School of Life Sciences, Faculty of Medicine, Tottori University, Nishimachi 86, Yonago, Tottori 683, Japan.
Hum Mol Genet. 1997 Nov;6(12):2127-33. doi: 10.1093/hmg/6.12.2127.
We have constructed mouse A9 hybrids containing a single normal human chromosome 15, via microcell-mediated chromosome transfer. Cytogenetic and DNA-polymorphic analyses identified mouse A9 hybrids that contained either a paternal or maternal human chromosome 15. Paternal specific expression of the known imprinted genes SNRPN (small nuclear ribonucleoprotein-associated polypeptide N gene) and IPW (imprinted gene in the Prader-Willi syndrome region) was maintained in the A9 hybrids. Using this system, we first demonstrated that human GABAAreceptor subunit genes, GABRB3 , GABRA5 and GABRG3 , were expressed exclusively from the paternal allele and that E6-AP (E6-associated protein or UBE3A ) was biallelically expressed. Moreover, the 5' portion of the GABRB3 gene was found to be hypermethylated on the paternal allele. Our data imply that GABAAreceptor subunit genes are imprinted and are possible candidates for Prader-Willi syndrome, and that this human monochromosomal hybrid system enables the efficient analysis of imprinted loci.
我们通过微细胞介导的染色体转移构建了含有一条正常人类15号染色体的小鼠A9杂种细胞。细胞遗传学和DNA多态性分析鉴定出含有父源或母源人类15号染色体的小鼠A9杂种细胞。已知的印记基因SNRPN（小核核糖核蛋白相关多肽N基因）和IPW（普拉德-威利综合征区域的印记基因）在A9杂种细胞中保持父源特异性表达。利用该系统，我们首次证明人类γ-氨基丁酸A型受体亚基基因GABRB3、GABRA5和GABRG3仅从父源等位基因表达，而E6-AP（E6相关蛋白或泛素蛋白连接酶3A）呈双等位基因表达。此外，发现GABRB3基因的5'部分在父源等位基因上发生高甲基化。我们的数据表明，γ-氨基丁酸A型受体亚基基因存在印记，可能是普拉德-威利综合征的候选基因，并且这种人类单染色体杂种细胞系统能够有效地分析印记位点。
