title: Brn3a target gene recognition in embryonic sensory neurons.
abstract: Numerous transcription factors have been identified which have profound effects on developing neurons. A fundamental problem is to identify genes downstream of these factors and order them in developmental pathways. We have previously identified 85 genes with changed expression in the trigeminal ganglia of mice lacking Brn3a, a transcription factor encoded by the Pou4f1 gene. Here we use locus-wide chromatin immunoprecipitation in embryonic trigeminal neurons to show that Brn3a is a direct repressor of two of these downstream genes, NeuroD1 and NeuroD4, and also directly modulates its own expression. Comparison of Brn3a binding to the Pou4f1 locus in vitro and in vivo reveals that not all high affinity sites are occupied, and several Brn3a binding sites identified in the promoters of genes that are silent in sensory ganglia are also not occupied in vivo. Site occupancy by Brn3a can be correlated with evolutionary conservation of the genomic regions containing the recognition sites and also with histone modifications found in regions of chromatin active in transcription and gene regulation, suggesting that Brn3a binding is highly context dependent.
authors.affiliation: Department of Psychiatry, 0603, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Lanier
authors.forename: Lely A
authors.initials: LA
authors.lastname: Quina
authors.forename: S Raisa
authors.initials: SR
authors.lastname: Eng
authors.forename: Eric
authors.initials: E
authors.lastname: Cox
authors.forename: Eric E
authors.initials: EE
authors.lastname: Turner
mesh_terms: D000107:Acetylation; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000502:physiology; D004622:Embryo, Mammalian / Q000166:cytology; D005786:Gene Expression Regulation; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009475:Neurons, Afferent / Q000378:metabolism / Q000502:physiology*; D050819:Transcription Factor Brn-3A / Q000235:genetics / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D006657:Histones; D009419:Nerve Tissue Proteins; D050819:Transcription Factor Brn-3A; C104516:Neurod4 protein, mouse; C494189:Pou4f1 protein, mouse; C093564:Neurogenic differentiation factor 1