title: Dynamic expression of transcription factor Brn3b during mouse cranial nerve development.
abstract: During development, transcription factor combinatorial codes define a large variety of morphologically and physiologically distinct neurons. Such a combinatorial code has been proposed for the differentiation of projection neurons of the somatic and visceral components of cranial nerves. It is possible that individual neuronal cell types are not specified by unique transcription factors but rather emerge through the intersection of their expression domains. Brn3a, Brn3b, and Brn3c, in combination with each other and/or transcription factors of other families, can define subgroups of retinal ganglion cells (RGC), spiral and vestibular ganglia, inner ear and vestibular hair cell neurons in the vestibuloacoustic system, and groups of somatosensory neurons in the dorsal root ganglia. The present study investigates the expression and potential role of the Brn3b transcription factor in cranial nerves and associated nuclei of the brainstem. We report the dynamic expression of Brn3b in the somatosensory component of cranial nerves II, V, VII, and VIII and visceromotor nuclei of nerves VII, IX, and X as well as other brainstem nuclei during different stages of development into adult stage. We find that genetically identified Brn3b(KO) RGC axons show correct but delayed pathfinding during the early stages of embryonic development. However, loss of Brn3b does not affect the anatomy of the other cranial nerves normally expressing this transcription factor.
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892.|Molecular Biology Center, Interdisciplinary Research Institute on Bio-Nano-Science, Babes-Bolyai University, Cluj-Napoca, Cluj, 400084, Romania.
authors.forename: Szilard
authors.initials: S
authors.lastname: Sajgo
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892.
authors.forename: Seid
authors.initials: S
authors.lastname: Ali
authors.affiliation: Molecular Biology Center, Interdisciplinary Research Institute on Bio-Nano-Science, Babes-Bolyai University, Cluj-Napoca, Cluj, 400084, Romania.|Institute of Biology, Romanian Academy, Bucharest, 060031, Romania.
authors.forename: Octavian
authors.initials: O
authors.lastname: Popescu
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892.
authors.forename: Tudor Constantin
authors.initials: TC
authors.lastname: Badea
mesh_terms: D000818:Animals; D003391:Cranial Nerves / Q000196:embryology* / Q000254:growth & development / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055879:Gene Knock-In Techniques; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D011247:Pregnancy; D050820:Transcription Factor Brn-3B / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D018398:Homeodomain Proteins; C085559:Pou4f2 protein, mouse; D050820:Transcription Factor Brn-3B
keywords: POU domain Brn3b; cranial nerves; facial nerve; glossopharyngeal nerve; optic nerve; transcription; trigeminal nerve; vagus nerve