Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea.
Department of Brain Sciences, DGIST, Daegu, Republic of Korea.
Elife. 2022 Oct 26;11:e78345. doi: 10.7554/eLife.78345.
The little skate , a cartilaginous fish, displays pelvic fin driven walking-like behavior using genetic programs and neuronal subtypes similar to those of land vertebrates. However, mechanistic studies on little skate motor circuit development have been limited, due to a lack of high-quality reference genome. Here, we generated an assembly of the little skate genome, with precise gene annotation and structures, which allowed post-genome analysis of spinal motor neurons (MNs) essential for locomotion. Through interspecies comparison of mouse, skate and chicken MN transcriptomes, shared and divergent gene expression profiles were identified. Comparison of accessible chromatin regions between mouse and skate MNs predicted shared transcription factor (TF) motifs with divergent ones, which could be used for achieving differential regulation of MN-expressed genes. A greater number of TF motif predictions were observed in MN-expressed genes in mouse than in little skate. These findings suggest conserved and divergent molecular mechanisms controlling MN development of vertebrates during evolution, which might contribute to intricate gene regulatory networks in the emergence of a more sophisticated motor system in tetrapods.
小鳐鱼，一种软骨鱼，利用与陆地脊椎动物相似的遗传程序和神经元亚型表现出类似行走的行为。然而，由于缺乏高质量的参考基因组，对小鳐鱼运动回路发育的机制研究一直受到限制。在这里，我们生成了小鳐鱼基因组的组装，具有精确的基因注释和结构，这使得对运动所必需的脊髓运动神经元（MN）的后基因组分析成为可能。通过对鼠、鳐鱼和鸡 MN 转录组的种间比较，确定了共享和分化的基因表达谱。在鼠和鳐鱼 MN 之间的可及染色质区域的比较预测了共享转录因子（TF）基序和分化的基序，这些基序可用于实现 MN 表达基因的差异调节。在鼠中，与小鳐鱼相比，在 MN 表达基因中观察到更多的 TF 基序预测。这些发现表明，在进化过程中，控制脊椎动物 MN 发育的保守和分化的分子机制可能有助于四足动物中更复杂的运动系统的出现的复杂基因调控网络。
