期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 108, 期 8, 页码 3395-3400出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1014411108
关键词
-
资金
- Wings for Life Foundation
- National Institutes of Health [DE16550, DE19440A1]
- National Institute of Dental and Craniofacial Research
- Foundation for Science and Technology, Portugal
Mammalian somatosensory topographic maps contain specialized neuronal structures that precisely recapitulate the spatial pattern of peripheral sensory organs. In the mouse, whiskers are orderly mapped onto several brainstem nuclei as a set of modular structures termed barrelettes. Using a dual-color iontophoretic labeling strategy, we found that the precise topography of barrelettes is not a result of ordered positions of sensory neurons within the ganglion. We next explored another possibility that formation of the whisker map is influenced by periphery-derived mechanisms. During the period of peripheral sensory innervation, several TGF-beta ligands are exclusively expressed in whisker follicles in a dynamic spatiotemporal pattern. Disrupting TGF-beta signaling, specifically in sensory neurons by conditional deletion of Smad4 at the late embryonic stage, results in the formation of abnormal barrelettes in the principalis and interpolaris brainstem nuclei and a complete absence of barrelettes in the caudalis nucleus. We further show that this phenotype is not derived from defective peripheral innervation or central axon outgrowth but is attributable to the misprojection and deficient segregation of trigeminal axonal collaterals into proper barrelettes. Furthermore, Smad4-deficient neurons develop simpler terminal arbors and form fewer synapses. Together, our findings substantiate the involvement of whisker-derived TGF-beta/Smad4 signaling in the formation of the whisker somatotopic maps.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据