Epigenetic regulation of lineage specification in colon epithelial cells

项目总结 结肠是一种有反应的组织，每3-4天就会更换一次上皮。冒号有专门的 为了自我更新和分化而分裂成特殊细胞类型的干细胞。分化的结肠细胞 具有不同的功能，包括吸收水分和分泌粘液。在许多组织中，分化是 由包括组蛋白修饰在内的表观遗传机制驱动。组蛋白H3赖氨酸36位甲基化(H3K36) 与转录活性部位的基因体相关。H3K36甲基化促进分化 以及干细胞在快速更新的组织中的维持，包括血液和睾丸。根据初步数据，我 假设H3K36甲基化决定细胞命运并加强结肠上皮细胞特性 细胞，特别是结肠细胞和杯状细胞系。为了解决这一假设，我将追求两个具体目标。 首先，我计划描述结肠上皮细胞中H3K36甲基化的特征。第二，我将确定 H3K36甲基化在结肠细胞识别中的功能作用尽管，在两个国家之间建立直接联系 由于系统中的冗余，特定的组蛋白修饰和细胞过程是具有挑战性的，我可以 利用在癌症中首次发现的赖氨酸(K)到蛋氨酸(M)的突变来克服这一障碍 患者精确抑制H3K36甲基化。我将结合多种尖端工具来专门追踪 并在小鼠和有机模型系统中操纵H3K36甲基化，以促进对 结肠中的染色质和谱系特征。我还将使用新的排序协议来净化不同的冒号 用于比较表观遗传学和转录分析的细胞群体。总的来说，这项工作意义重大 因为它将确定H3K36甲基化在控制细胞类型特定基因表达和 结肠中的血统决定。揭示组蛋白修饰在结肠内稳态中所起的作用是第一步 了解这些调节机制是如何在结肠炎/癌症等疾病中分解的，并可能 影响人类健康。

PROJECT SUMMARY The colon is a responsive tissue, and the epithelium replaces itself every 3-4 days. The colon has dedicated stem cells that divide for self-renewal and differentiation into specialized cell types. Differentiated colon cells perform distinct functions including water absorption and mucus secretion. In many tissues, differentiation is driven by epigenetic mechanisms including histone modifications. Methylation of histone H3 at lysine 36 (H3K36) is associated with gene bodies at sites of transcriptional activity. H3K36 methylation contributes to differentiation and stem cell maintenance in rapidly renewing tissues including blood and testes. Based on preliminary data, I hypothesize that H3K36 methylation governs cell fate decisions and reinforces cell identity in colon epithelial cells, specifically colonocyte and goblet cell lineages. To address this hypothesis, I will pursue two specific aims. First, I plan to characterize the H3K36 methylation signature in colon epithelial cells. Second, I will determine the functional role of H3K36 methylation in colon cell identity. Although, establishing a direct connection between specific histone modifications and cellular processes is challenging due to redundancies in the system, I can overcome this obstacle by taking advantage of a lysine (K)-to-methionine (M) mutation first discovered in cancer patients to precisely suppress H3K36 methylation. I will combine multiple cutting-edge tools to specifically trace and manipulate H3K36 methylation in mice and organoid model systems to advance the understanding of chromatin and lineage specification in the colon. I will also utilize novel sorting protocols to purify distinct colon cell populations for comparative epigenetic and transcriptional analysis. Collectively, this work is significant because it will establish the role of H3K36 methylation in controlling cell-type specific gene expression and lineage decisions in the colon. Revealing the role histone modifications play in colon homeostasis is the first step to understanding how these regulatory mechanisms break down in diseases such as colitis/cancer and could impact human health.