The Transcription Factor Pou3f1 Sheds Light on the Development and Molecular Diversity of Glutamatergic Cerebellar Nuclear Neurons in the Mouse

Abstract

The cerebellar nuclear (CN) neurons are a molecularly heterogeneous population whose specification into the different cerebellar nuclei is defined by the expression of varying sets of transcription factors. Here, we present a novel molecular marker, Pou3f1, that delineates specific sets of glutamatergic CN neurons. The glutamatergic identity of Pou3f1+ cells was confirmed by: (1) the co-expression of vGluT2, a cell marker of glutamatergic neurons; (2) the lack of co-expression between Pou3f1 and GAD67, a marker of GABAergic neurons; (3) the co-expression of Atoh1, the master regulator required for the production of all cerebellar glutamatergic lineages; and (4) the absence of Pou3f1-expressing cells in the Atoh1-null cerebellum. Furthermore, the lack of Pax6 and Tbr1 expression in Pou3f1+ cells reveals that Pou3f1-expressing CN neurons specifically settle in the interposed and dentate nuclei. In addition, the Pou3f1-labeled glutamatergic CN neurons can be further classified by the expression of Brn2 and Irx3. The results of the present study align with previous findings highlighting that the survival of the interposed and dentate CN neurons is largely independent of Pax6. More importantly, the present study extends the field’s collective knowledge of the molecular diversity of cerebellar nuclei.

Cerebellum Lecture: the Cerebellar Nuclei—Core of the Cerebellum

“…Lateral CN [321] E13.5 in NTZ [341] Not Granule cells; a subset of unipolar brush cells [345] Developmental function for CN unknown This table includes genes expressed throughout development: from the proliferative zones (E9.5-E12) to their residency in and around the NTZ (E13-E15), to their final positions in the CN (early postnatal to adult). The table summarizes the seminal papers that identify these cells, their patterns of expression, and their suggested functions.…”

Integrative single-cell characterization of hypothalamus sex-differential and obesity-associated genes and regulatory elements

“…In both mouse and human GABAergic and glutamatergic neuronal populations, we observed a large number of shared TFBSs, such as HOXA7, MEOX2, NHLH2, RFX1 and RFX3 ( Extended Data Fig.3a,b ). Analysis of mouse and human GABAergic neurons for the TFBSs that have the most enriched motif scores, found many shared TFBS to be enriched in these neurons, such as distal-less homeobox 5 ( DLX5 ), well-known to regulate GABAergic neurons and control behavior and metabolism 83 , even-skipped homeobox 1 ( EVX1 ), which is required for GABAergic neuron development 84 , and POU3F1 which regulates neural differentiation 85 ( Fig.3c ). In the glutamatergic neuronal populations, we found mouse and human cells to show TFBS enrichment for the RFX TF family, achaete-scute family BHLH transcription factor 1 ( ASCL1 ), that is required for dopaminergic neurons differentiation from iPSC cells 86 and THAP11 or RONIN, known regulators of neural stem cell differentiation 87 ( Fig.3c ).…”

“…3a,b). Analysis of mouse and human GABAergic neurons for the TFBSs that have the most enriched motif scores, found many shared TFBS to be enriched in these neurons, such as distal-less homeobox 5 (DLX5), well-known to regulate GABAergic neurons and control behavior and metabolism 83 , even-skipped homeobox 1 (EVX1), which is required for GABAergic neuron development 84 , and POU3F1 which regulates neural differentiation 85 (Fig. 3c).…”

A spatial-temporal map of glutamatergic neurogenesis in embryonic cerebellar nuclei uncovers a high degree of cellular heterogeneity

“…They migrate as part of the so-called rostral RL migratory stream, tangentially along the surface of the cerebellar primordium 17 , and reach the nuclear transitory zone (NTZ) as early as E11.5 17,18 . While migrating, neurons downregulate Atoh1 and upregulate several transcription factors, including Pax6 (E13.5) 19 and Pou3f1 (E10.5) 20 . In the NTZ, the nascent CN express Tbr2 and Tbr1 19 , which mark a subset of neurons of the MED, as well as Brn2 (Pou3f2), Olig2 and/or Irx3, which are thought to mainly give rise to LAT and INT neuronal subsets 20 .…”

“…While migrating, neurons downregulate Atoh1 and upregulate several transcription factors, including Pax6 (E13.5) 19 and Pou3f1 (E10.5) 20 . In the NTZ, the nascent CN express Tbr2 and Tbr1 19 , which mark a subset of neurons of the MED, as well as Brn2 (Pou3f2), Olig2 and/or Irx3, which are thought to mainly give rise to LAT and INT neuronal subsets 20 .…”