Thanatos-Associated Protein 11 (Thap11) in Human Embryonic Stem Cells

我们在HES细胞中发现了一种新的蛋白质，命名为Thap11(Thanatos-Associated Protein 11)。Thap11是 胚胎干细胞分化的抑制因子。与大多数其他因素不同的是，塔普11似乎直接 参与转录调控和表观遗传修饰。Thapl 1有一个假定的DMA结合 与果蝇P元件(一种DMA)的DMA结合结构域显著相似的结构域 转座子)。这表明，就像P元件一样，thapl 1可能作为一种位点特异性转录 调制器，我们随后证实了这一可能性。有趣的是，其中一个最引人注目的基因 在ES细胞中由thapl 1上调的是Suz12(Zest12的抑制子，表观遗传修饰物抑制 HES细胞分化)。此外，thapl 1还与DNA甲基转移酶样蛋白3相互作用。 (DnmtSL)，并具有自身的NAD+依赖的组蛋白脱乙酰酶(HDAC)活性，使其成为一种新的HDAC 就凭它自己的力量。 我们的总体假设是，thapl 1在控制HES细胞的自我更新中起着关键作用。 阻断分化。为了检验这一假设，将(A)分析thapl 1是如何控制 Suz12，并确定thapl 1的其他靶基因；对这些基因(包括Suz12)的了解是 至关重要，因为它们是控制未分化状态的转录网络的一部分 (多能)HES细胞；(B)剖析thapl 1和DnmtSL之间的关系；我们将研究如何 Thapl 1与DnmtSL相互作用，如果这调节了基因的位点特异性DMA甲基化(Suz12和 其他)；(C)分析TAPL 1依赖NAD+的HDAC活性。这些信息将使我们能够 调节Thpl 1‘S的HDAC活性，如果我们的 基本假设是正确的。 由于thapl 1作为转录因子并且还参与至少两种表观遗传机制， DNA甲基化和组蛋白去乙酰化，它可能代表了转录之间的重要联系 HES细胞中的控制和表观遗传学。针对Thapl1的特定遗传和药物干预 功能可能允许控制HES细胞的自我更新和分化。

We identified a novel protein, designated Thap11 (Thanatos-associated protein 11) in hES cells. Thap11 is an inhibitor of differentiation in ES cells. In contrast to most other factors, Thap11 seems to be directly involved with both, transcriptional control and epigenetic modification. Thapl 1 has a putative DMA-binding domain that shows significant similarity to the DMA-binding domain of the Drosophila P element (a DMA transposon). This suggested that, like the P element, Thapl 1 might act as a site-specific transcriptional modulator, a possibility we subsequently confirmed. Interestingly, one of the genes most strikingly upregulated by Thapl 1 in ES cells is Suz12 (Suppressor of Zeste 12, epigenetic modifier that suppresses differentiation in hES cells). In addition Thapl 1 interacts with DMA methyltransferase like protein 3 (DnmtSL), and has its own NAD+-dependent histone deacetylase (HDAC) activity, making it a novel HDAC in its own right. Our overall hypothesis is that Thapl 1 plays a critical role in controlling self-renewal of hES cells by blocking differentiation. To test this hypothesis will (a) analyze how Thapl 1 controls the expression of Suz12 and identify additional target genes of Thapl 1; knowledge of these genes (including Suz12) is critical since they are part of the transcriptional network that controls the undifferentiated state (pluripotency) of hES cells; (b) dissect the relationship between Thapl 1 and DnmtSL; we will study how Thapl 1 interacts with DnmtSL and if this modulates site-specific DMA methylation of genes (Suz12 and others); (c) analyze the NAD+-dependent HDAC activity of Thapl 1. This information will allow us to modulate Thapl 1's HDAC activity, an effect that in turn should help control differentiation of hES cells if our primary Hypothesis is correct. Since Thapl 1 acts as a transcriptional factor and is also involved in at least two epigenetic mechanisms, DNA methylation and histone deacetylation, it may represent an important link between transcriptional control and epigenetics in hES cells. Specific genetic and pharmacologic interventions targeting Thapl1 function may allow control of self-renewal and differentiation of hES cells.