Expression of EphB receptors and EphrinB Ligands in the developing chick auditory brainstent
Expression of EphB receptors and EphrinB Ligands in the developing chick auditory brainstent
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DOI：
10.1002/cne.10399
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发表时间：
2002-10-07
影响因子：
2.5
通讯作者：
Rubel, EW
中科院分区：
文献类型：
--
作者：
Cramer, KS;Karam, SD;Rubel, EW
大细胞核（NM）位于鸟类听觉脑干，接受来自第VIII神经的听觉输入，并向两侧投射至板状核（NL）。这种投射保持双耳分离，同侧NM投射到NL的背侧树突，对侧NM投射到NL的腹侧树突。我们已经开始研究影响NL细胞离散区域输入分离的分子信号。我们以前表明，Eph受体，EphA 4，选择性地表达在背侧NL神经元从胚胎（E）9天到E11，当NM轴突生长到NL神经元。这种不对称分布表明EphA 4在双耳分离期间充当引导分子。我们在这里报告的发育变化的表达的其他两个Eph受体，EphB 2和EphB 5，和两个配体，ephrin-B1和ephrin-B2，在鸡听觉脑干。这些蛋白质在NM-NL投射成熟期间在听觉核中表达。EphB 2、EphB 5和ephrin-B1在背侧和腹侧NL神经元中以及在E10-E12的脑干中线处表达。在这个年龄，肝配蛋白-B2，EphB受体和EphA 4的配体，在NL细胞体和NM-NL轴突中表达。这些蛋白质的表达减少，在孵化后的年龄检查。这些结果表明，Eph家族的几个成员参与了细胞核的成熟及其投射。此外，ephrin-B2在生长的轴突中可能与不对称表达的EphA 4在双耳分离的建立过程中相互作用。(C)2002 Wiley-Liss，Inc.
Nucleus magnocellularis (NM) in the avian auditory, brainstem receives auditory input from nerve the VIIIth and projects bilaterally to nucleus laminaris (NL). This projection preserves binaural segregation in that ipsilateral NM projects to dorsal dendrites of NL and contralateral NM projects to ventral dendrites of NL. We have begun to examine the molecular signals that influence segregation of inputs onto discrete regions of NL cells. We previously showed that the Eph receptor, EphA4, is expressed selectively in the dorsal NL neuropil from embryonic day (E) 9 to Ell, when NM axons grow into the NL neuropil. This asymmetric distribution suggests that EphA4 acts as a guidance molecule during binaural segregation. We report here on the developmental changes in the expression of two other Eph receptors, EphB2 and EphB5, and two ligands, ephrin-B1 and ephrin-B2, in the chick auditory brainstem. These proteins are expressed in the auditory nuclei during the maturation of the NM-NL projection. EphB2, EphB5, and ephrin-B1 are expressed in dorsal and ventral NL neuropil and at the midline of the brainstem at E10-E12. At this age, ephrin-B2, a ligand for EphB receptors and for EphA4, is expressed in NL cell bodies and NM-NL axons. The expression of these proteins diminishs in the posthatch ages examined. These results suggest that several members of the Eph family are involved in maturation of the nuclei and their projections. Moreover, ephrin-B2 in growing axons may interact with the asymmetrically expressed EphA4 during the establishment of binaural segregation. (C) 2002 Wiley-Liss, Inc.