Gabriel J M, Higgins M J, Gebuhr T C, Shows T B, Saitoh S, Nicholls R D
Department of Genetics, Case Western Reserve University School of Medicine, University Hospitals of Cleveland, 10900 Euclid Avenue, Cleveland, OH 44106-4955, USA.
Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14857-62. doi: 10.1073/pnas.95.25.14857.
Somatic-cell hybrids have been shown to maintain the correct epigenetic chromatin states to study developmental globin gene expression as well as gene expression on the active and inactive X chromosomes. This suggests the potential use of somatic-cell hybrids containing either a maternal or a paternal human chromosome as a model system to study known imprinted genes and to identify as-yet-unknown imprinted genes. Testing gene expression by using reverse transcription followed by PCR, we show that functional imprints are maintained at four previously characterized 15q11-q13 loci in hybrids containing a single human chromosome 15 and at two chromosome 11p15 loci in hybrids containing a single chromosome 11. In contrast, three gamma-aminobutyric acid type A receptor subunit genes in 15q12-q13 are nonimprinted. Furthermore, we have found that differential DNA methylation imprints at the SNRPN promoter and at a CpG island in 11p15 are also maintained in somatic-cell hybrids. Somatic-cell hybrids therefore are a valid and powerful system for studying known imprinted genes as well as for rapidly identifying new imprinted genes.
体细胞杂种已被证明能维持正确的表观遗传染色质状态，以研究发育过程中的珠蛋白基因表达以及活性和失活X染色体上的基因表达。这表明，含有母源或父源人类染色体的体细胞杂种有可能作为一种模型系统，用于研究已知的印记基因并鉴定尚未知晓的印记基因。通过逆转录后进行PCR来检测基因表达，我们发现，在含有单条人类15号染色体的杂种中，四个先前已被鉴定的15q11 - q13位点以及在含有单条11号染色体的杂种中的两个11p15位点上，功能性印记得以维持。相比之下，位于15q12 - q13的三个γ-氨基丁酸A型受体亚基基因是非印记的。此外，我们还发现，SNRPN启动子和11p15中一个CpG岛处的差异DNA甲基化印记在体细胞杂种中也得以维持。因此，体细胞杂种是研究已知印记基因以及快速鉴定新印记基因的一个有效且强大的系统。
