title: Developmental expression of Synaptotagmin isoforms in single calyx of Held-generating neurons.
abstract: The large glutamatergic calyx of Held synapse in the auditory brainstem has become a powerful model for studying transmitter release mechanisms, but the molecular bases of presynaptic function at this synapse are not well known. Here, we have used single-cell quantitative PCR (qPCR) to study the developmental expression of all major Synaptotagmin (Syt) isoforms in putative calyx of Held-generating neurons (globular bushy cells) of the ventral cochlear nucleus. Using electrophysiological criteria and the expression of marker genes including VGluTs (vesicular glutamate transporters), Ca(2+) binding proteins, and the transcription factor Math5, we identified a subset of the recorded neurons as putative calyx of Held-generating bushy cells. At postnatal days 12-15 these neurons expressed Syt-2 and Syt-11, and also Syt-3, -4, -7 and -13 at lower levels, whereas Syt-1 and -9 were absent. Interestingly, early in development (at P3-P6), immature bushy cells expressed a larger number of Syt-isoforms, with Syt-1, Syt-5, Syt-9 and Syt-13 detected in a significantly higher percentage of neurons. Our study sheds light on the molecular properties of putative calyx of Held-generating neurons and shows the developmental regulation of the Syt-isoform expression profile in a single neuron type.
authors.affiliation: Laboratory of Synaptic Mechanisms, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Le
authors.initials: L
authors.lastname: Xiao
authors.forename: Yunyun
authors.initials: Y
authors.lastname: Han
authors.forename: Heike
authors.initials: H
authors.lastname: Runne
authors.forename: Heather
authors.initials: H
authors.lastname: Murray
authors.forename: Olexiy
authors.initials: O
authors.lastname: Kochubey
authors.forename: Ruth
authors.initials: R
authors.lastname: Luthi-Carter
authors.forename: Ralf
authors.initials: R
authors.lastname: Schneggenburger
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001306:Auditory Pathways / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins / Q000032:analysis; D001933:Brain Stem / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000032:analysis; D020869:Gene Expression Profiling / Q000379:methods; D018507:Gene Expression Regulation, Developmental; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000502:physiology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000378:metabolism*; D050857:Synaptotagmins / Q000235:genetics / Q000378:metabolism*; D050496:Vesicular Glutamate Transport Proteins / Q000032:analysis
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D002135:Calcium-Binding Proteins; D020033:Protein Isoforms; D050857:Synaptotagmins; D050496:Vesicular Glutamate Transport Proteins