Mapendano Christophe K, Kishino Tatsuya, Miyazaki Kazumi, Kondo Shinji, Yoshiura Koh-Ichiro, Hishikawa Yoshitaka, Koji Takehiko, Niikawa Norio, Ohta Tohru
Department of Human Genetics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
CREST, Japan Science and Technology Agency, Kawaguchi, Japan.
J Hum Genet. 2006;51(3):236-243. doi: 10.1007/s10038-005-0351-8. Epub 2006 Jan 21.
The human chromosome 15q11-q13, or mouse chromosome 7C, is an imprinting domain controlled by bipartite imprinting centers (ICs): Prader-Willi syndrome (PWS)-IC and Angelman syndrome (AS)-IC. PWS-IC functions to maintain the paternal epigenotype on the paternal chromosome in somatic cells, while AS-IC plays a role in the establishment of the maternal epigenetic mark at PWS-IC in the female germline or early embryos. Several alternative exons and promoters of Snurf-Snrpn (SNRPN upstream reading frame-small nuclear ribonucleoprotein polypeptide N) are expressed as "IC transcripts". Previous studies have shown that IC-transcript expression is restricted to the brain. We studied expression of the mouse IC-transcript in tissues including brain and oocytes as well as in cultured neurons and glia cells by RT-PCR and by in situ hybridization (ISH) in oocytes. The IC transcript was strongly expressed in brain (especially in neurons) and ovary (especially in oocytes and granulosa cells), while no expression was found in other tissues. This was confirmed by quantitative analysis and ISH. Expression levels in the brain were 7-fold higher compared to those in ovaries. ISH signals were observed in oocytes and granulosa cells of the secondary and developing follicles. These findings, together with previous data, suggest that the IC transcript may be associated with the establishment of PWS-IC methylation on the maternal chromosome as an AS-IC cis-acting element.
人类染色体15q11 - q13，或小鼠染色体7C，是一个由双分型印记中心（ICs）控制的印记区域：普拉德 - 威利综合征（PWS）-IC和安吉尔曼综合征（AS）-IC。PWS-IC的功能是在体细胞中维持父本染色体上的父本表观基因型，而AS-IC在雌性生殖系或早期胚胎中PWS-IC处母本表观遗传标记的建立中发挥作用。Snurf-Snrpn（SNRPN上游阅读框 - 小核核糖核蛋白多肽N）的几个可变外显子和启动子被表达为“IC转录本”。先前的研究表明，IC转录本的表达仅限于大脑。我们通过RT-PCR以及在卵母细胞中进行原位杂交（ISH），研究了小鼠IC转录本在包括大脑和卵母细胞在内的组织以及培养的神经元和神经胶质细胞中的表达。IC转录本在大脑（特别是在神经元中）和卵巢（特别是在卵母细胞和颗粒细胞中）中强烈表达，而在其他组织中未发现表达。这通过定量分析和ISH得到证实。大脑中的表达水平比卵巢中的高7倍。在次级卵泡和发育卵泡的卵母细胞和颗粒细胞中观察到ISH信号。这些发现与先前的数据一起表明，IC转录本可能作为AS-IC顺式作用元件与母本染色体上PWS-IC甲基化的建立相关。
