Spatial rearrangement of Purkinje cell subsets forms the transverse and longitudinal compartmentalization in the mouse embryonic cerebellum

Transversely oriented lobules and longitudinally arrayed stripes of Purkinje cell subsets subdivide the cerebellar cortex into multiple compartments that are involved in diverse functions. In the mammalian cerebellum, anterior, and posterior lobules, which are involved in somatosensorimotor function, show an alternation of aldolase C (zebrin II) ‐positive and ‐negative stripes, whereas the central lobules (lobules VIb–VII and crus I), which are implicated in nonmotor functions, show a laterally expanded arrangement solely of aldolase C‐positive stripes. To understand the developmental process of this compartmental pattern, we identified groups of Purkinje cell subsets in the entire mouse cerebellum at embryonic day (E) 14.5 by staining Purkinje cell subset markers. We then tracked four major domains of Protocadherin 10 (Pcdh10)‐positive Purkinje cell subsets (medial, dorsal, central, and mid‐lateral subsets), which were clearly demarcated during E14.5–17.5. These domains of Purkinje cell subsets shifted predominantly in the longitudinal direction to be positioned in the anterior and posterior lobules. However, a particular portion of the medial and mid‐lateral domains, and the whole of the central domain shift in the lateral direction to be positioned in the central lobules. The results indicate that while the longitudinal shift of domains of Purkinje cell subsets forms the longitudinally striped compartments in the anterior and posterior cerebellum, the lateral shift of particular domains of Purkinje cell subsets underlies the laterally expanded arrangement of stripes in central lobules. Thus, the rearrangement of Purkinje cell subsets in the embryonic cerebellum is critically related to the compartmental organization in the mammalian cerebellum. The authors clarified three‐dimensional distribution of Protocadherin 10‐positive Purkinje cell subsets in the mouse cerebellum at embryonic day (E) 14.5 and tracked them from E14.5 to E17.5. The revealed rearrangement processes of Purkinje cell subsets show how the cerebellar compartmentalization is formed in the central cerebellar lobules.