title: Temporal patterns of gene expression during calyx of held development.
abstract: Relating changes in gene expression to discrete developmental events remains an elusive challenge in neuroscience, in part because most neural territories are comprised of multiple cell types that mature over extended periods of time. The medial nucleus of the trapezoid body (MNTB) is an attractive vertebrate model system that contains a nearly homogeneous population of neurons, which are innervated by large glutamatergic nerve terminals called calyces of Held (CH). Key steps in maturation of CHs and MNTB neurons, including CH growth and competition, occur very quickly for most cells between postnatal days (P)2 and P6. Therefore, we characterized genome-wide changes in this system, with dense temporal sampling during the first postnatal week. We identified 541 genes whose expression changed significantly between P0-6 and clustered them into eight groups based on temporal expression profiles. Candidate genes from each of the eight profile groups were validated in separate samples by qPCR. Our tissue sample permitted comparison of known glial and neuronal transcripts and revealed that monotonically increasing or decreasing expression profiles tended to be associated with glia and neurons, respectively. Gene ontology revealed enrichment of genes involved in axon pathfinding, cell differentiation, cell adhesion and extracellular matrix. The latter category included elements of perineuronal nets, a prominent feature of MNTB neurons that is morphologically distinct by P6, when CH growth and competition are resolved onto nearly all MNTB neurons. These results provide a genetic framework for investigation of general mechanisms responsible for nerve terminal growth and maturation.
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Kolson
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jun
authors.initials: J
authors.lastname: Wan
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.|Department of Otolaryngology HNS, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wu
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: Marlin
authors.initials: M
authors.lastname: Dehoff
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: Ashley N
authors.initials: AN
authors.lastname: Brandebura
authors.affiliation: Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jiang
authors.initials: J
authors.lastname: Qian
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.|Department of Otolaryngology HNS, West Virginia University School of Medicine, Morgantown, West Virginia.|Department of Biochemistry, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Mathers
authors.affiliation: Sensory Neuroscience Research Center, West Virginia University School of Medicine, Morgantown, West Virginia.|Center for Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia.|Department of Otolaryngology HNS, West Virginia University School of Medicine, Morgantown, West Virginia.
authors.forename: George A
authors.initials: GA
authors.lastname: Spirou
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D001369:Axons / Q000378:metabolism*; D001933:Brain Stem / Q000254:growth & development; D005109:Extracellular Matrix / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051379:Mice; D009457:Neuroglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*
keywords: MNTB; calyx of held; development; microarray; perineuronal net