biostudies-literatureRavenscroft TANICHD NIH HHSThe Cullen FoundationHoward Hughes Medical InstituteThe Research Foundation - FlandersNIHGouvernement du Canada | Canadian Institutes of Health ResearchNIH HHSNIGMS NIH HHS7999-8024https://www.ebi.ac.uk/biostudies/studies/S-EPMC7574647biostudies-literatureUnknown40(42)In multipolar vertebrate neurons, action potentials (APs) initiate close to the soma, at the axonal initial segment. Invertebrate neurons are typically unipolar with dendrites integrating directly into the axon. Where APs are initiated in the axons of invertebrate neurons is unclear. Voltage-gated sodium (Na_V) channels are a functional hallmark of the axonal initial segment in vertebrates. We used an intronic <i>Minos</i>-Mediated Integration Cassette to determine the endogenous gene expression and subcellular localization of the sole Na_V channel in both male and female <i>Drosophila</i>, <i>para</i> Despite being the only Na_V channel in the fly, we show that only 23 ± 1% of neurons in the embryonic and larval CNS express <i>para</i>, while in the adult CNSThe Journal of neuroscience : the official journal of the Society for Neuroscience<i>Drosophila</i> Voltage-Gated Sodium Channels Are Only Expressed in Active Neurons and Are Localized to Distal Axonal Initial Segment-like Domains.PMC7574647P50 HD103555U54 HD0830921199518NR35 GM127102P40 OD018537R01 GM067858R35GM127102MFE-164712Ravenscroft TATepe BMakhzami SMarcogliese PCLee PTJanssens JAerts SHolmes TCBellen HJfalse<i>Drosophila</i> Voltage-Gated Sodium Channels Are Only Expressed in Active Neurons and Are Localized to Distal Axonal Initial Segment-like Domains.In multipolar vertebrate neurons, action potentials (APs) initiate close to the soma, at the axonal initial segment. Invertebrate neurons are typically unipolar with dendrites integrating directly into the axon. Where APs are initiated in the axons of invertebrate neurons is unclear. Voltage-gated sodium (Na_V) channels are a functional hallmark of the axonal initial segment in vertebrates. We used an intronic <i>Minos</i>-Mediated Integration Cassette to determine the endogenous gene expression and subcellular localization of the sole Na_V channel in both male and female <i>Drosophila</i>, <i>para</i> Despite being the only Na_V channel in the fly, we show that only 23 ± 1% of neurons in the embryonic and larval CNS express <i>para</i>, while in the adult CNS2020-01-01T00:00:00Z2020 Oct2026-04-07T15:09:15.434Z2022-02-09T15:00:52.286ZS-EPMC75746473292888910.1523/jneurosci.0142-20.202010.1523/JNEUROSCI.0142-20.2020