Sakaguchi Takehisa, Nishimoto Masazumi, Miyagi Satoru, Iwama Atsushi, Morita Yohei, Iwamori Naoki, Nakauchi Hiromitsu, Kiyonari Hiroshi, Muramatsu Masami, Okuda Akihiko
Division of Developmental Biology, Research Center for Genomic Medicine, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1241, Japan.
Mol Cell Biol. 2006 Sep;26(17):6557-70. doi: 10.1128/MCB.00729-06.
Many genes have been identified that are specifically expressed in multiple types of stem cells in their undifferentiated state. It is generally assumed that at least some of these putative "stemness" genes are involved in maintaining properties that are common to all stem cells. We compared gene expression profiles between undifferentiated and differentiated embryonic stem cells (ESCs) using DNA microarrays. We identified several genes with much greater signal in undifferentiated ESCs than in their differentiated derivatives, among them the putative stemness gene encoding junctional adhesion molecule B (Jam-B gene). However, in spite of the specific expression in undifferentiated ESCs, Jam-B mutant ESCs had normal morphology and pluripotency. Furthermore, Jam-B homozygous mutant mice are fertile and have no overt developmental defects. Moreover, we found that neural and hematopoietic stem cells recovered from Jam-B mutant mice are not impaired in their ability to self-renew and differentiate. These results demonstrate that Jam-B is dispensable for normal mouse development and stem cell identity in embryonic, neural, and hematopoietic stem cells.
许多基因已被鉴定出在多种类型的未分化干细胞中特异性表达。一般认为，这些假定的“干性”基因中至少有一些参与维持所有干细胞共有的特性。我们使用DNA微阵列比较了未分化和分化的胚胎干细胞（ESC）之间的基因表达谱。我们鉴定出几个在未分化的ESC中信号比其分化衍生物中强得多的基因，其中包括编码连接粘附分子B的假定干性基因（Jam-B基因）。然而，尽管Jam-B在未分化的ESC中特异性表达，但Jam-B突变的ESC具有正常的形态和多能性。此外，Jam-B纯合突变小鼠可育且无明显发育缺陷。而且，我们发现从Jam-B突变小鼠中分离出的神经和造血干细胞在自我更新和分化能力方面并未受损。这些结果表明，Jam-B对于正常小鼠发育以及胚胎、神经和造血干细胞中的干细胞特性而言并非必需。
