SNAP-25 requirement for dendritic growth of hippocampal neurons.
Structure and dimension of the dendritic arbor are important determinants of information processing by the nerve cell, but mechanisms and molecules involved in dendritic growth are essentially unknown. We investigated early mechanisms of dendritic growth using mouse fetal hippocampal neurons in primary culture, which form processes during the first week in vitro. We detected a key component of regulated exocytosis, SNAP-25 (synaptosomal associated protein of 25 kDa), in axons and axonal terminals as well as in dendrites identified by the occurrence of the dendritic markers transferrin receptor and MAP2. Selective inactivation of SNAP-25 by botulinum neurotoxin A (BoNTA) resulted in inhibition of axonal growth and of vesicle recycling in axonal terminals. In addition, dendritic growth of hippocampal pyramidal and granule neurons was significantly inhibited by BoNTA. In contrast, cleavage of synaptobrevin by tetanus toxin had an effect on neither axonal nor dendritic growth. Our observations indicate that SNAP-25, but not synaptobrevin, is involved in constitutive axonal growth and dendrite formation by hippocampal neurons.
Grosse
G
G
Institut für Anatomie, Universitätsklinikum Charité, Humboldt-Universität Berlin, Germany.
Grosse
J
J
Tapp
R
R
Kuchinke
J
J
Gorsleben
M
M
Fetter
I
I
Höhne-Zell
B
B
Gratzl
M
M
Bergmann
M
M
D000818:Animals; D001369:Axons / Q000502:physiology; D019274:Botulinum Toxins, Type A / Q000494:pharmacology; D002478:Cells, Cultured; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004705:Endocytosis / Q000187:drug effects; D005089:Exocytosis / Q000187:drug effects; D005333:Fetus; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins; D051379:Mice; D008815:Mice, Inbred Strains; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000502:physiology*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology; D011990:Receptors, Transferrin / Q000378:metabolism; D013572:Synaptic Vesicles / Q000502:physiology; D050825:Synaptosomal-Associated Protein 25
D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011990:Receptors, Transferrin; C494209:Snap25 protein, mouse; D050825:Synaptosomal-Associated Protein 25; D019274:Botulinum Toxins, Type A