Migration, early axonogenesis, and Reelin-dependent layer-forming behavior of early/posterior-born Purkinje cells in the developing mouse lateral cerebellum

Takaki Miyata,Mitsuhiro Hashimoto,Makoto Masaoka,Masaharu Ogawa,Akira Sakakibara,Mayumi Okamoto,Ayano Kawaguchi,Yuichi Ono

doi:10.1186/1749-8104-5-23

Takaki Miyata, Mitsuhiro Hashimoto + Show 6 more

Open Access

https://doi.org/10.1186/1749-8104-5-23

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Abstract

BackgroundCerebellar corticogenesis begins with the assembly of Purkinje cells into the Purkinje plate (PP) by embryonic day 14.5 (E14.5) in mice. Although the dependence of PP formation on the secreted protein Reelin is well known and a prevailing model suggests that Purkinje cells migrate along the 'radial glial' fibers connecting the ventricular and pial surfaces, it is not clear how Purkinje cells behave in response to Reelin to initiate the PP. Furthermore, it is not known what nascent Purkinje cells look like in vivo. When and how Purkinje cells start axonogenesis must also be elucidated.ResultsWe show that Purkinje cells generated on E10.5 in the posterior periventricular region of the lateral cerebellum migrate tangentially, after only transiently migrating radially, towards the anterior, exhibiting an elongated morphology consistent with axonogenesis at E12.5. After their somata reach the outer/dorsal region by E13.5, they change 'posture' by E14.5 through remodeling of non-axon (dendrite-like) processes and a switchback-like mode of somal movement towards a superficial Reelin-rich zone, while their axon-like fibers remain relatively deep, which demarcates the somata-packed portion as a plate. In reeler cerebella, the early born posterior lateral Purkinje cells are initially normal during migration with anteriorly extended axon-like fibers until E13.5, but then fail to form the PP due to lack of the posture-change step.ConclusionsPreviously unknown behaviors are revealed for a subset of Purkinje cells born early in the posteior lateral cerebellum: tangential migration; early axonogenesis; and Reelin-dependent reorientation initiating PP formation. This study provides a solid basis for further elucidation of Reelin's function and the mechanisms underlying the cerebellar corticogenesis, and will contribute to the understanding of how polarization of individual cells drives overall brain morphogenesis.

Highlights

Cerebellar corticogenesis begins with the assembly of Purkinje cells into the Purkinje plate (PP) by embryonic day 14.5 (E14.5) in mice
Purkinje-cell-specific markers [26,29,30] and slice culture [31], the present study focused on the developing mouse lateral cerebellum until E14.5 and unveiled three important behaviors of a subset of Purkinje cells born at E10.5 in the posterior region: tangential migration; early axonogenesis; and Reelin-dependent ‘posture’ change initiating PP formation
Purkinje cells that initiate PP formation at E14.5 are born on E10.5 in a posterior ventricular zone (VZ) As the first step in elucidating the mechanism of the emergence of the PP, we analyzed the identity of cells incorporated into the initial PP

Summary

Introduction

Cerebellar corticogenesis begins with the assembly of Purkinje cells into the Purkinje plate (PP) by embryonic day 14.5 (E14.5) in mice. The dependence of PP formation on the secreted protein Reelin is well known and a prevailing model suggests that Purkinje cells migrate along the ‘radial glial’ fibers connecting the ventricular and pial surfaces, it is not clear how Purkinje cells behave in response to Reelin to initiate the PP. It is not known what nascent Purkinje cells look like in vivo.

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