title: Brn-3.0 expression identifies early post-mitotic CNS neurons and sensory neural precursors.
abstract: The mammalian POU-domain factor Brn-3.0 (Brn-3, Brn-3a) is a member of the POU-IV class of transcription factors which resemble the C. elegans factor unc-86 in structure, DNA-binding properties and expression in subsets of sensory neurons. Using specific antisera, we have explored the expression of Brn-3.0 in the early development of the mouse nervous system. Brn-3.0 expression begins at embryonic day 8.5 (E8.5) in a specific set of midbrain tectal neurons whose time and place of appearance are consistent with the earliest CNS neurons previously identified using non-specific markers of neural differentiation. By E9.5, Brn-3.0 immunoreactivity also identifies early CNS neurons in the hindbrain and spinal cord. In the peripheral sensory ganglia, Brn-3.0 expression is first observed at E9.0 in migrating precursors of the trigeminal ganglion, followed by the other sensory cranial and dorsal root ganglia, in a rostral to caudal sequence. Double-label immunofluorescence with Brn-3.0 and the markers of cell division PCNA and BrdU demonstrate that Brn-3.0 is restricted to the post-mitotic phase of CNS development. In the sensory cranial and dorsal root ganglia, however, Brn-3.0 is expressed in dividing neural precursors, suggesting that the nature or timing of developmental events controlled by Brn-3.0 are distinct in the CNS and peripheral neurons. Restriction of Brn-3.0 expression to post-mitotic CNS neurons demonstrates that Brn-3.0 is not required for neurogenesis or patterning of the neuroepithelium in the CNS, but suggests a role in specification of mature neuronal phenotypes.
authors.affiliation: Department of Psychiatry, University of California, San Diego, USA.
authors.forename: N G
authors.initials: NG
authors.lastname: Fedtsova
authors.forename: E E
authors.initials: EE
authors.lastname: Turner
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D002490:Central Nervous System / Q000737:chemistry / Q000166:cytology / Q000196:embryology*; D004268:DNA-Binding Proteins / Q000032:analysis*; D017950:Ganglia, Sensory / Q000737:chemistry / Q000196:embryology; D005865:Gestational Age; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009475:Neurons, Afferent / Q000737:chemistry* / Q000166:cytology; D010641:Phenotype; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D013234:Stem Cells / Q000737:chemistry* / Q000166:cytology; D050818:Transcription Factor Brn-3; D050819:Transcription Factor Brn-3A; D014157:Transcription Factors / Q000032:analysis*
chemical_list: D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; C494189:Pou4f1 protein, mouse; D018809:Proliferating Cell Nuclear Antigen; D050818:Transcription Factor Brn-3; D050819:Transcription Factor Brn-3A; D014157:Transcription Factors