[植物生理] 植物細胞的再生機制 20191011 PNAS

Cell-type–specific transcriptome and histone modification dynamics during cellular reprogramming in the Arabidopsis stomatal lineage

Laura R. Lee, Diego L. Wengier, and Dominique C. Bergmann

Abstract

Plant cells maintain remarkable developmental plasticity, allowing them to clonally reproduce and to repair tissues following wounding; yet plant cells normally stably maintain consistent identities. Although this capacity was recognized long ago, our mechanistic understanding of the establishment, maintenance, and erasure of cellular identities in plants remains limited. Here, we develop a celltype– specific reprogramming system that can be probed at the genome-wide scale for alterations in gene expression and histone modifications. We show that relationships among H3K27me3, H3K4me3, and gene expression in single cell types mirror trends from complex tissue, and that H3K27me3 dynamics regulate guard cell identity. Further, upon initiation of reprogramming, guard cells induce H3K27me3-mediated repression of a regulator of woundinduced callus formation, suggesting that cells in intact tissues may have mechanisms to sense and resist inappropriate dedifferentiation. The matched ChIP-sequencing (seq) and RNA-seq datasets created for this analysis also serve as a resource enabling inquiries into the dynamic and global-scale distribution of histone modifications in single cell types in plants.

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暸解在細胞重新設定身份的過程中，阿拉伯芥保衛細胞後代的轉錄組與組織蛋白（Histone）被修飾的動態變化

摘要

植物細胞維持著非常驚人的發育彈性，在受到損傷後可以利用重新設定身份並製造相同的細胞來治療受損的組織。但是，一般而言，植物細胞一直都很穩定的維持著特定的細胞身份。雖然這個身份重新設定的現象很早就被認識，但是對於這個重設現象的建立、維持以及移除細胞身份的機制，仍然有許多未知。在此，我們發展出了一套針對特定細胞的重設系。這個系統可以偵測整個基因體中，基因表現的改變，以及組織蛋白修飾的變化。我們發現，在單一個細胞中，H3K27me3以及H3K4me3的修飾和基因表現表現的走向，在複雜的組織中，有著鏡像的趨勢，並且，H3K27me3的動態，調控了保衛細胞的身分。進一步來說，在身份重設的起始時期，保衛細胞會誘導經由增加H3K27me3的機制，來抑制一個癒傷組織形成因子的表現。這個結果顯示了，在完整組織中的細胞，可能有個機制，可以偵查並且抵抗不正確的去分化。在這個檢視中所產生、互相符合的免疫組織蛋白沈澱定序與核糖核酸定序資料，可以作為在調查整個植物體、單一個細胞的組織蛋白修飾動態研究中，一個非常好的資料來源。