Kdm2b基因与毗邻长非编码RNA调控大脑皮层发育的研究

Kdm2b, a component of Polycomb repressive complex, plays essential roles in self-renewal and differentiation of embryonic and adult stem cells, reprogramming of somatic cell and tumorigenesis. Long non-coding RNAs are recently found to be key regulators in a variety of developmental and pathogenetic processes. We recently found that the long transcript of Kdm2b and its neighboring long non-coding RNA are specifically expressed in the intermediate neural progenitor cells and newborn neurons, and perturbations of their expression in vivo and in vitro significantly affect neuronal differentiation and migration, indicating their roles in cell-fate transitions of neural progenitor cells in cortical development. In this project, we will study their roles in cell-fate specification of neural progenitor cells using comprehensive cell biology, biochemical, embryonic and genetic means. Kdm2b knock-in mouse lines will be established to study its detail expression pattern and map the cell-fate lineage during cortical development. In utero electroporation, gene-ablation mouse model and in vitro culture of neural progenitor cells will be used to study whether the two molecules are indeed essential for cortical development. Furthermore, we will study whether the transcriptions of lncRNA-M14 and different isoforms of Kdm2b are mutually regulated; and the underlying epigenetic mechanisms that they utilize to regulate chromatin modification and gene expressions. This study will expand our knowledge regarding epigenetic regulation in organogenesis and regeneration, and may therefore have potential clinical implications.

多梳抑制复合物组分Kdm2b在胚胎和成体干细胞自我更新和分化、体细胞重编程以及肿瘤发生中起核心作用。长非编码RNA也在器官发育、多种生理和病理过程发挥重要的基因调控功能。我们的前期研究发现Kdm2b的长编码产物和其毗邻长非编码RNA特异表达于胚胎期小鼠大脑皮层的中间神经前体细胞与新生神经元，体内和体外实验证明干预它们的表达能显著影响神经元的分化和迁移，提示这两个分子在皮层发育中发挥关键的命运决定功能。本研究将应用遗传学示踪方法，阐明这两个分子在小鼠皮层发育中的表达情况和子代细胞的命运；应用小鼠胚胎子宫内电转、基因剔除小鼠和神经前体细胞体外分化平台研究这两个分子在神经前体细胞命运决定和皮层发育中的作用；还将研究Kdm2b不同转录产物与毗邻长非编码RNA间的表达调控关系，以及它们影响细胞命运决定的表观遗传学机制。上述研究能加深对表观遗传调控机制在器官发育和再生过程中的认识。

多梳抑制复合物组分Kdm2b在胚胎和成体干细胞自我更新和分化、体细胞重编程以及肿瘤发生中起核心作用。长非编码RNA也在器官发育、多种生理和病理过程发挥重要的基因调控功能。我们的前期研究发现Kdm2b的长编码产物和其毗邻长非编码RNA-LncKdm2b特异表达于胚胎期小鼠大脑皮层的中间神经前体细胞与新生神经元，体内和体外实验证明干预它们的表达能显著影响神经元的分化和迁移，提示这两个分子在皮层发育中发挥关键的命运决定功能。组织原位杂交发现LncKdm2b在皮层投射神经元的早期分化过程中瞬时表达。LncKdm2b通过顺式调节控制基因Kdm2b的转录，LncKdm2b具有内在激活功能，并通过与蛋白质hnRNPAB结合促进Kdm2b基因启动子区域形成允许转录的染色质环境。谱系追踪和表型分析实验表明，LncKdm2b和Kdm2b在皮层投射神经元正确分化和迁移过程中发挥至关重要的作用。此外，KDM2B依赖于其富含亮氨酸的重复序列（LRR）发挥作用，但与多梳抑制复合物PRC1相关的功能无关。这些发现揭示了一种依赖于lncRNA的皮层神经元分化调控机制，加深了对表观遗传调控机制特别是lncRNA在器官发育和再生过程中的认识。主要研究成果曾在Neuron和Cell Stem Cell送外审（peer review）；现在eLife修回，获得了较为正面的评价，即将发表的可能性很大。在本项目的部分资助下，本课题组还发表SCI研究论文4篇，还有一篇研究论文在FASEB Journal修回。培养了数名研究生。多次参加国际和国内会议并做报告。