Dissecting the cell autonomous and non-autonomous effects of DNMT1 deletion in cortical somatostatinergic interneurons

The development of cortical circuits, made up of excitatory neurons and inhibitory interneurons, is a fine-tuned and vital process during brain development. Aberrations affecting the establishment of these circuits are implicated in several neuropsychiatric and neurological disorders. While excitatory neurons originate in cortical proliferative zones, inhibitory interneurons migrate from the basal telencephalon into the cortex. This migration is regulated by intrinsic genetic programs and extrinsic cues. Here, we aimed to identify the role of the DNA methyltransferase 1 (DNMT1) in controlling the expression of key genes implicated in the development and migration of post-mitotic somatostatin-positive interneurons as well as its impact on the rest of the cortical population. Medial cortical tissue was dissected from brains of E16.5 mice with or without a conditional knockout of Dnmt1 in somatostatinergic interneurons. The nuclei were extracted via sucrose gradient ultracentrifugation and fixed. Following library preparation based on a split-and-pool approach, the samples were sequenced.由兴奋性神经元与抑制性中间神经元构成的皮层环路发育，是脑发育过程中经过精细调控的关键进程。干扰此类环路构建的异常改变，与多种神经精神疾病及神经系统疾病密切相关。兴奋性神经元起源于皮层增殖区，而抑制性中间神经元则从基底端脑迁移至皮层，该迁移过程受到内在遗传程序与外在信号的共同调控。本研究旨在明确DNA甲基转移酶1（DNA methyltransferase 1, DNMT1）在调控有丝分裂后生长抑素阳性中间神经元发育与迁移相关关键基因表达中的作用，以及其对其余皮层细胞群体的影响。我们从E16.5小鼠的脑组织中分离内侧皮层组织，受试小鼠的生长抑素能中间神经元分别携带或不携带Dnmt1条件性基因敲除；随后通过蔗糖梯度超速离心法提取细胞核并进行固定；基于分池（split-and-pool）策略完成文库构建后，对样本进行了测序。