Cerebellar granule cell precursors (GCPs) and granule cells (GCs) constitute a good model system to investigate proliferation of neural precursors and differentiation of neurons. During development, GCPs proliferate in the outer external granule cell layer (outer EGL) and then exit the cell cycle in the inner EGL to become GCs, which inwardly migrate to the inner granule cell layer (IGL). Misregulation of GCP proliferation or GC differentiation leads to maldevelopment of the cerebellum and the formation of a cerebellar tumor, medulloblastoma. Despite many efforts in this field, the mechanisms underlying GC development remain elusive. In this study, we performed detailed immunostaining in the developing cerebellum, with particular focus on GCPs and GCs, looking at several transcription factors, signaling molecules, cell cycle regulators, some of which are known to regulate neural development. Interestingly, we found distinct distribution patterns of certain proteins within the outer and inner EGL, suggesting the existence of subpopulations of GCPs and GCs in those layers. This study provides a basis for future studies on the cerebellar GC development and medulloblastoma.

小脑颗粒细胞前体（GCP）和颗粒细胞（GC）构成了研究神经前体增殖和神经元分化的良好模型系统。在发育过程中，GCP在外部外部颗粒细胞层（外部EGL）中增殖，然后退出内部EGL中的细胞周期，变成GC，然后向内迁移到内部颗粒细胞层（IGL）。GCP增殖或GC分化的调控异常会导致小脑发育不良，并形成小脑肿瘤髓母细胞瘤。尽管在该领域做出了许多努力，但GC开发背后的机制仍然难以捉摸。在这项研究中，我们在发育中的小脑中进行了详细的免疫染色，特别关注GCP和GC，研究了几种转录因子，信号分子，细胞周期调节剂，其中一些已知调节神经发育。有趣的是，我们在外部和内部EGL中发现了某些蛋白质的独特分布模式，这表明在这些层中存在GCP和GC的亚群。该研究为小脑GC的发展和髓母细胞瘤的进一步研究提供了基础。