Identification of an early subset of cerebellar nuclei neurons in mice

Abstract Cerebellar nuclei (CN) neurons serve as the primary output of the cerebellum and originate from the cerebellar primordium at the early stages of cerebellar development. Employing various methodologies, we have characterized a specific subset of CN neurons that do not originate from the rhombic lip and the ventricular zone of the cerebellar primordium. Embryos were collected from timed pregnant mice at early stages of development and processed for immunohistochemistry (IHC), Western blotting, in situ hybridization (ISH), embryonic culture, DiI labeling, or flow cytometry analysis (FCM). Our findings indicate that a subset of CN neurons expressing α-synuclein (SNCA), OTX2, MEIS2, and p75NTR (NGFR) are located in the rostro-ventral (rv) region of the nuclear transitory zone (NTZ), while CN neurons derived from the rhombic lip are positioned in the caudo-dorsal (cd) area of the NTZ in the cerebellar primordium. Utilizing Otx2-GFP and Atoh1-/- mice, we have determined that these cells do not originate from the germinal zone of the cerebellar primordium. These results suggest the existence of a novel extrinsic germinal zone for the cerebellar primordium, possibly the mesencephalon, from which early CN neurons originate.