多能性幹細胞の分化過程における染色体の機能的構造変化

我的研究项目调查了人类胚胎干细胞(HES)分化为一种特殊类型的细胞(称为滋养层细胞)所涉及的细胞事件。该项目的主要部分集中在了解当HES细胞失去多能性并分化为特化的滋养层细胞时，染色质(细胞核的结构)如何变化。我专门研究了一种叫做“组蛋白”的蛋白质，它是染色质的基本单位。我特别感兴趣的是一种叫做“组蛋白2A变异体Z”的组蛋白。我对H2AZ很感兴趣，因为当它被修饰时，可以对染色质结构产生不同的影响。这些修饰主要涉及被称为“乙酰化”或“甲基化”的小分子的添加。为了研究H2AZ修饰的变化，我使用了一种名为免疫荧光素的技术(用荧光标记我想研究的蛋白质或RNA分子)，然后用非常灵敏的显微镜对细胞核成像，然后在我的实验室对捕获的图像执行一种特殊类型的图像处理和分析。使用这些技术，我发现干细胞中的H2AZ乙酰化状态在诱导分化的治疗后变化非常迅速(短短12小时)。我研究了在HES分化下，H_2AZ的乙酰化和去乙酰化的蛋白质复合体，发现H_2AZ的脱乙酰化是进行分化的关键。

My research project investigated the cellular events involved in the differentiation of human embryonic stem (hES) cells into a specialized type of cell called a trophoblast cell. The major part of the project was centered on understanding how chromatin (the architecture of the nucleus) changes when hES cells loose their pluripotency and differentiate into the specialized trophoblast cells. I specifically studied proteins called 'histones' which are the basic unit of chromatin. I was particularly interested in a type of histone protein called 'histone 2A variant Z' (H2AZ). I was interested in H2AZ because it can have different effects on the chromatin architecture when by becoming modified. These modifications primarily concern the addition of small molecules called "acetylation" or "methylation". To study the changes in the modification of H2AZ I used a technique called immunofluorencese (to fluorescently label the proteins or RNA molecules I want to study) I then imaged the cell nucleus with a very sensitive microscope and then perform a specialized type of image processing and analysis that was writen in my laboratory on the captured image. Using these techniques, I found that status of H2AZ acetylation in the stem cell changes very quickly (in as little as 12 hours) following treatment to induce differentiation. I have studied the protein complexes that both acetylate and de-acetylate H2AZ under hES differentiation and found that de-acetylation of H2AZ is critical for differentiation to proceed.