PDF(Pubmed)
Abstract：
The nervous system emerges from a series of genetic programs that generate a remarkable array of neuronal cell types. Each cell type must acquire a distinct anatomical position, morphology, and function, enabling the generation of specialized circuits that drive animal behavior. How are these diverse cell types and circuits patterned along the anterior-posterior (A-P) axis of the animal body? Hox genes encode transcription factors that regulate cell fate and patterning events along the A-P axis of the nervous system. While most of our understanding of Hox-mediated control of neuronal development stems from studies in segmented animals like flies, mice, and zebrafish, important new themes are emerging from work in a non-segmented animal: the nematode Caenorhabditis elegans. Studies in C. elegans support the idea that Hox genes are needed continuously and across different life stages in the nervous system; they are not only required in dividing progenitor cells, but also in post-mitotic neurons during development and adult life. In C. elegans embryos and young larvae, Hox genes control progenitor cell specification, cell survival, and neuronal migration, consistent with their neural patterning roles in other animals. In late larvae and adults, C. elegans Hox genes control neuron type-specific identity features critical for neuronal function, thereby extending the Hox functional repertoire beyond early patterning. Here, we provide a comprehensive review of Hox studies in the C. elegans nervous system. To relate to readers outside the C. elegans community, we highlight conserved roles of Hox genes in patterning the nervous system of invertebrate and vertebrate animals. We end by calling attention to new functions in adult post-mitotic neurons for these paradigmatic regulators of cell fate.
摘要：
神经系统来自一系列遗传程序，这些程序产生了一系列非凡的神经元细胞类型。每种细胞类型必须获得不同的解剖位置，形态学,和功能，能够产生驱动动物行为的专门电路。这些不同的细胞类型和回路是如何沿着动物体的前后（A-P）轴图案化的？Hox基因编码转录因子，这些转录因子沿着神经系统的A-P轴调节细胞命运和图案化事件。虽然我们对Hox介导的神经元发育控制的大部分理解源于对像苍蝇这样的分段动物的研究，老鼠,和斑马鱼,重要的新主题正在非分段动物的工作中出现：线虫秀丽隐杆线虫。秀丽隐杆线虫的研究支持这样的观点，即在神经系统的不同生命阶段持续需要Hox基因；它们不仅是分裂祖细胞所必需的，而且在发育和成年期间的有丝分裂后神经元中也是如此。在秀丽隐杆线虫的胚胎和幼体中,Hox基因控制祖细胞规格，细胞存活,和神经元迁移，与它们在其他动物中的神经模式作用一致。在晚期幼虫和成虫中，C.elegansHox基因控制神经元类型特定的身份特征，对神经元功能至关重要，从而将Hox功能库扩展到早期模式之外。这里,我们对秀丽隐杆线虫神经系统的Hox研究进行了全面综述。为了与秀丽隐士社区之外的读者联系，我们强调了Hox基因在构建无脊椎动物和脊椎动物神经系统中的保守作用。最后，我们呼吁关注这些典型的细胞命运调节剂在成人有丝分裂后神经元中的新功能。
