Directional asymmetry of the zebrafish epithalamus guides dorsoventral innervation of the midbrain target
Directional asymmetry of the zebrafish epithalamus guides dorsoventral innervation of the midbrain target
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DOI：
10.1242/dev.02046
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发表时间：
2005-11-01
期刊：
影响因子：
4.6
通讯作者：
Halpern, ME
中科院分区：
文献类型：
--
作者：
Gamse, JT;Kuan, YS;Halpern, ME
斑马鱼的上皮体由松果体复合体和两侧背束核组成，为探索脊椎动物大脑的左右差异如何产生提供了一个有价值的模型。松果体旁位于松果体左侧，左侧松果体束较大，神经组织扩张致密，基因表达模式与右侧松果体束明显不同。在淋巴结信号的影响下，顶骨旁的定位决定了缰状核不对称的方向，从而决定了缰状核投射到中脑靶点——脚间核（IPN）的左右起源。在顶旁反转的斑马鱼中，神经元从左缰状突起突起到一个更有限的腹侧IPN区域，而右缰状轴突通常会突起。相反，来自右缰的传出信号采用左侧缰神经元典型的更广泛的背腹侧IPN投射模式。与剩菜相关的KCTD（含钾通道四聚域）基因家族的三个成员在左右束中表达不同，其模式定义了不对称亚核。分子不对称延伸到缰神经传出的蛋白质水平，提供了额外的证据，表明左轴突和右轴突终止于中脑靶点的不同背腹侧区域。激光介导的顶骨旁消融术破坏了小脑的不对称性，从而改变了支配神经轴突的背腹侧分布。结果表明，前脑背侧性影响中脑连接的形成及其分子性质。
The zebrafish epithalamus, consisting of the pineal complex and flanking dorsal habenular nuclei, provides a valuable model for exploring how left-right differences could arise in the vertebrate brain. The parapineal lies to the left of the pineal and the left habenula is larger, has expanded dense neuropil, and distinct patterns of gene expression from the right habenula. Under the influence of Nodal signaling, positioning of the parapineal sets the direction of habenular asymmetry and thereby determines the left-right origin of habenular projections onto the midbrain target, the interpeduncular nucleus (IPN). In zebrafish with parapineal reversal, neurons from the left habenula project to a more limited ventral IPN region where right habenular axons would normally project. Conversely, efferents from the right habenula adopt a more extensive dorsoventral IPN projection pattern typical of left habenular neurons. Three members of the leftover-related KCTD (potassium channel tetramerization domain containing) gene family are expressed differently by the left and right habenula, in patterns that define asymmetric subnuclei. Molecular asymmetry extends to protein levels in habenular efferents, providing additional evidence that left and right axons terminate within different dorsoventral regions of the midbrain target. Laser-mediated ablation of the parapineal disrupts habenular asymmetry and consequently alters the dorsoventral distribution of innervating axons. The results demonstrate that laterality of the dorsal forebrain influences the formation of midbrain connections and their molecular properties.