Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachioji, Tokyo, Japan.
Dev Biol. 2011 Jun 1;354(1):144-50. doi: 10.1016/j.ydbio.2011.03.006. Epub 2011 Mar 21.
Nodal signaling plays an essential role in the establishment of left-right asymmetry in various animals. However, it is largely unknown how Nodal signaling is involved in the establishment of the left-right asymmetric morphology. In this study, the role of Nodal signaling in the left-right asymmetric ocellus formation in the ascidian, Ciona intestinalis was dealt with. During the development of C. intestinalis, the ocellus pigment cell forms on the midline and moves to the right side of the midline. Then, the photoreceptor cells form on the right side of the sensory vesicle (SV). Ci-Nodal is expressed on the left side of the SV in the developing tail bud embryo. When Nodal signaling is inhibited, the ocellus pigment cell form but remain on the midline, and expression of marker genes of the ocellus photoreceptor cells is ectopically detected on the left side as well as on the right side of the SV in the larva. Furthermore, Ci-Rx, which is essential for the ocellus differentiation, turns out to be negatively regulated by the Nodal signaling on the left side of the SV, even though it is required for the right-sided photoreceptor formation. These results indicate that Nodal signaling controls the left-right asymmetric ocellus formation in the development of C. intestinalis.
节点信号在各种动物的左右不对称建立中起着至关重要的作用。然而，节点信号如何参与左右不对称形态的建立在很大程度上是未知的。在这项研究中，处理了节点信号在海鞘 Ciona intestinalis 的左右不对称眼点形成中的作用。在 C. intestinalis 的发育过程中，眼点色素细胞在中线上形成，并移动到中线的右侧。然后，感光细胞在感觉囊（SV）的右侧形成。Ci-Nodal 在发育尾芽胚胎的 SV 的左侧表达。当节点信号被抑制时，眼点色素细胞形成，但仍在中线上，并且在幼虫的 SV 的左侧和右侧异位检测到眼点感光细胞的标记基因的表达。此外，Ci-Rx，它对于眼点分化是必需的，结果被 SV 左侧的节点信号负调控，尽管它对于右侧感光形成是必需的。这些结果表明，节点信号控制了 C. intestinalis 发育中的左右不对称眼点形成。
