Powers Amanda K, Boggs Tyler E, Gross Joshua B
Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
Dev Biol. 2018 Sep 15;441(2):252-261. doi: 10.1016/j.ydbio.2018.04.001. Epub 2018 Apr 6.
Developmental patterning is a complex biological phenomenon, involving integrated cellular and molecular signaling across diverse tissues. In Astyanax cavefish, the lateral line sensory system is dramatically expanded in a region of the cranium marked by significant bone abnormalities. This system provides the opportunity to understand how facial bone patterning can become altered through sensory system changes. Here we investigate a classic postulation that mechanosensory receptor neuromasts seed intramembranous facial bones in aquatic vertebrates. Using an in vivo staining procedure across individual life history, we observed infraorbital canal neuromasts serving as sites of ossification for suborbital bones. The manner in which cavefish departed from the stereotypical and symmetrical canal neuromast patterns of closely-related surface-dwelling fish were associated with specific changes to the suborbital bone complex. For instance, bony fusion, rarely observed in surface fish, was associated with shorter distances between canal neuromasts in cavefish, suggesting that closer canal neuromasts result in bony fusions. Additionally, cavefish lacking the sixth suborbital bone (SO6) uniformly lacked the associated (sixth) canal neuromast. This study suggests that patterning of canal neuromasts may impact spatial position of suborbital bones across development. The absence of an eye and subsequent orbital collapse in cavefish appears to influence positional information normally inherent to the infraorbital canal. These alterations result in coordinated changes to adult neuromast and bone structures. This work highlights complex interactions between visual, sensory and bony tissues during development that explain certain abnormal craniofacial features in cavefish.
发育模式是一种复杂的生物学现象，涉及不同组织间细胞和分子信号的整合。在墨西哥丽脂鲤中，侧线感觉系统在颅骨的一个区域显著扩展，该区域有明显的骨骼异常。这个系统为理解面部骨骼模式如何通过感觉系统的变化而改变提供了契机。在这里，我们研究一个经典的假设，即机械感觉受体神经丘在水生脊椎动物的膜内成骨面部骨骼中起种子作用。通过对个体生命历程进行体内染色程序，我们观察到眶下管神经丘作为眶下骨的骨化位点。墨西哥丽脂鲤偏离与其亲缘关系密切的表层鱼类典型且对称的管神经丘模式的方式，与眶下骨复合体的特定变化相关。例如，在表层鱼类中很少观察到的骨融合，与墨西哥丽脂鲤管神经丘之间较短的距离有关，这表明距离更近的管神经丘会导致骨融合。此外，缺少第六眶下骨（SO6）的墨西哥丽脂鲤一致缺少相关的（第六个）管神经丘。这项研究表明，管神经丘的模式可能会影响整个发育过程中眶下骨的空间位置。墨西哥丽脂鲤眼睛的缺失以及随后的眼眶塌陷似乎影响了眶下管通常固有的位置信息。这些改变导致成年神经丘和骨骼结构的协调变化。这项工作突出了发育过程中视觉、感觉和骨骼组织之间复杂的相互作用，这些相互作用解释了墨西哥丽脂鲤某些异常的颅面特征。
