Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan.
Sci Rep. 2017 Feb 13;7:42403. doi: 10.1038/srep42403.
The expression of 19 connexin (Cx) isoforms was observed in the mouse embryonic stem (ES) cell line, EB3. Their expression patterns could be classified into either pluripotent state-specific, differentiating stage-specific, or non-specific Cxs. We focused on Cx30.3 as typical of the first category. Cx30.3 was pluripotent state-specific and upregulated by leukemia inhibitory factor (LIF), a specific cytokine that maintains the pluripotent state of ES cell, via a Jak signaling pathway. Cx30.3 protein was localized to both the cell membrane and cytosol. The dynamic movement of Cx30.3 in the cell membrane was suggested by the imaging analysis by means of overexpressed Cx30.3-EGFP fusion protein. The cytosolic portion was postulated to be a ready-to-use Cx pool. The Cx30.3 expression level in ES cell colonies dramatically decreased immediately after their separation into single cells. It was suggested that mRNA for Cx30.3 and Cx30.3 protein might be decomposed more rapidly than mRNA for Cx43 and Cx43 protein, respectively. These indicate possible involvement of Cx30.3 in the rapid formation and/or decomposition of gap junctions; implying a functional relay between Cx30.3 and other systems such as adhesion proteins.
在小鼠胚胎干细胞 (ES) 细胞系 EB3 中观察到 19 种连接蛋白 (Cx) 异构体的表达。它们的表达模式可分为多能状态特异性、分化阶段特异性或非特异性 Cx。我们专注于 Cx30.3，它是第一类的典型代表。Cx30.3 是多能状态特异性的，通过 Jak 信号通路被白血病抑制因子 (LIF) 上调，LIF 是一种维持 ES 细胞多能状态的特异性细胞因子。Cx30.3 蛋白定位于细胞膜和细胞质。通过过表达 Cx30.3-EGFP 融合蛋白的成像分析，提示 Cx30.3 在细胞膜中的动态运动。细胞质部分被假设为一个现成的 Cx 池。Cx30.3 在 ES 细胞集落中的表达水平在它们分离成单细胞后立即急剧下降。这表明 Cx30.3 和 Cx30.3 蛋白的 mRNA 可能比 Cx43 和 Cx43 蛋白的 mRNA 更快分解。这表明 Cx30.3 可能参与了缝隙连接的快速形成和/或分解；暗示 Cx30.3 与其他系统（如粘附蛋白）之间存在功能联系。
