Tomás-Roca Laura, Corral-San-Miguel Rubén, Aroca Pilar, Puelles Luis, Marín Faustino
Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, and IMIB (Instituto Murciano de Investigación Biosanitaria), 30100, Murcia, Spain.
Department of Human Genetics, Nijmegen Center for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
Brain Struct Funct. 2016 Mar;221(2):815-38. doi: 10.1007/s00429-014-0938-y. Epub 2014 Nov 9.
The medulla oblongata is the caudal portion of the vertebrate hindbrain. It contains major ascending and descending fiber tracts as well as several motor and interneuron populations, including neural centers that regulate the visceral functions and the maintenance of bodily homeostasis. In the avian embryo, it has been proposed that the primordium of this region is subdivided into five segments or crypto-rhombomeres (r7-r11), which were defined according to either their parameric position relative to intersomitic boundaries (Cambronero and Puelles, in J Comp Neurol 427:522-545, 2000) or a stepped expression of Hox genes (Marín et al., in Dev Biol 323:230-247, 2008). In the present work, we examine the implied similar segmental organization of the mouse medulla oblongata. To this end, we analyze the expression pattern of Hox genes from groups 3 to 8, comparing them to the expression of given cytoarchitectonic and molecular markers, from mid-gestational to perinatal stages. As a result of this approach, we conclude that the mouse medulla oblongata is segmentally organized, similarly as in avian embryos. Longitudinal structures such as the nucleus of the solitary tract, the dorsal vagal motor nucleus, the hypoglossal motor nucleus, the descending trigeminal and vestibular columns, or the reticular formation appear subdivided into discrete segmental units. Additionally, our analysis identified an internal molecular organization of the migrated pontine nuclei that reflects a differential segmental origin of their neurons as assessed by Hox gene expression.
延髓是脊椎动物后脑的尾部部分。它包含主要的上行和下行纤维束以及几个运动神经元和中间神经元群体，包括调节内脏功能和维持身体内环境稳定的神经中枢。在鸟类胚胎中，有人提出该区域的原基被细分为五个节段或隐节段（r7 - r11），这些节段是根据它们相对于体节间边界的旁节位置（Cambronero和Puelles，《比较神经学杂志》427:522 - 545，2000年）或Hox基因的阶梯式表达（Marín等人，《发育生物学》323:230 - 247，2008年）来定义的。在本研究中，我们研究了小鼠延髓隐含的类似节段组织。为此，我们分析了3至8组Hox基因的表达模式，并将其与从妊娠中期到围产期特定细胞结构和分子标记的表达进行比较。通过这种方法，我们得出结论，小鼠延髓是节段性组织的，与鸟类胚胎类似。纵向结构，如孤束核、迷走神经背运动核、舌下运动核、三叉神经和前庭下行柱或网状结构，似乎被细分为离散的节段单元。此外，我们的分析确定了迁移的脑桥核的内部分子组织，这反映了通过Hox基因表达评估的其神经元的不同节段起源。
