拟南芥根表皮细胞分化模式形成过程中组蛋白去乙酰化酶HDA19的调控机制研究

Pattern formation is a fundamental question for understanding the development of multicellular organism. The differentiation of Arabidopsis root epidermis is a well-characterized model system for plant development study. The root epidermal cells develop into hair and non-hair cells according to their spatial relationship with the inner cortex cells. It is known that positional information from cortex tissue can determine the epidermal cell fate by regulating spatial distribution of pattern genes. Previous work by our lab indicated that histone deacetylase (HDAC) could mediate the unknown positional information. Following, functional studies of HDA18, a member of HDAC family, revealed that HDA18 acted through directly regulating the transcription of several kinase genes. Besides, we found hda6 and hda19 mutants also showed abnormal root epidermis differentiation pattern. Especially in hda19 mutant the periclinal division of epidermis and cortex cells was irregular. Based on these previous studies, in this proposed project, we will carry on to study the regulatory mechanism of HDA19 in detail. We plan to analyze whether and how HDA19 regulates the spatial expression of pattern genes, and to identify the direct target genes of HDA19 and then to investigate their regulatory mechanism. Besides, the HDA19 interacting protein is also our goal and we will try to reveal the meanings of the interaction for root epidermis differentiation. Through these genetical and molecular studies of HDA19 function, we believe we will provide more information and new insight for understanding the regulatory mechanism of positional information in root epidermis differentiation process.

模式形成是多细胞生物发育中的核心问题之一。拟南芥根表皮细胞根据其与皮层细胞之间的空间位置关系分化为根毛和非根毛细胞的现象是一个在植物中有很好研究基础的模式形成现象。目前已知来自皮层细胞的位置信息影响模式基因表达而决定表皮细胞的分化命运。本实验室前期工作表明组蛋白去乙酰化酶（HDAC）参与位置信息的介导；HDAC家族成员之一HDA18通过调节一批激酶基因的转录而发挥介导作用。此外，我们还发现HDAC家族的另外两个成员HDA6和HDA19的单基因突变体也产生根表皮分化模式异常的表型。本项目将在前期工作基础上，对HDA19的功能进行系统研究，包括确定HDA19是否通过调控模式基因的表达而发挥作用、筛选HDA19靶基因并分析其调控机制、寻找HDA19互作蛋白并分析互作所产生的影响。我们相信对HDA19基因功能的研究必将能够为理解根表皮细胞分化模式形成过程中位置信息介导机制提供全新的视角。

本课题在原定研究计划框架内，顺利完成了相关实验，确定了HDA19通过与决定内皮层细胞特征的基因SCR在皮层/内皮层前体细胞（CEI））内互作，共同调控皮层特征基因，影响皮层分化，从而影响根表皮细胞分化的模式形成。