首页 | 本学科首页   官方微博 | 高级检索  
     


Ventral specification and perturbed boundary formation in the mouse midbrain in the absence of Hedgehog signaling.
Authors:Jennifer L Fogel  Chin Chiang  Xi Huang  Seema Agarwala
Affiliation:Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78712-0248, USA.
Abstract:Although Hedgehog (HH) signaling plays a critical role in patterning the ventral midbrain, its role in early midbrain specification is not known. We examined the midbrains of sonic hedgehog (Shh) and smoothened (Smo) mutant mice where HH signaling is respectively attenuated and eliminated. We show that some ventral (Evx1+) cell fates are specified in the Shh-/- mouse in a Ptc1- and Gli1-independent manner. HH-independent ventral midbrain induction was further confirmed by the presence of a Pax7-negative ventral midbrain territory in both Shh-/- and Smo-/- mice at and before embryonic day (E) 8.5. Midbrain signaling centers are severely disrupted in the Shh-/- mutant. Interestingly, dorsal markers are up-regulated (Wnt1, Gdf7, Pax7), down-regulated (Lfng), or otherwise altered (Zic1) in the Shh-/- midbrain. Together with the increased cell death seen specifically in Shh-/- dorsal midbrains (E8.5-E9), our results suggest specific regulation of dorsal patterning by SHH, rather than a simple deregulation due to its absence.
Keywords:HH‐independent ventral midbrain specification  midbrain–hindbrain boundary  size regulation  roof plate  oculomotor neurons  dopaminergic neurons  Evx1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号