Dynamin 1 antisense oligonucleotide treatment prevents neurite formation in cultured hippocampal neurons

Dynamin 1 (D100) is a microtubule-activated GTPase that is believed to play a role in the early steps of receptor-mediated endocytosis. Previous studies on the characterization of the Drosophila dynamin gene homolog, known as shibire, suggest that this protein may also participate in the formation of neuronal processes. To understand the role of rat brain dynamin 1 in neuronal morphogenesis, we correlated the intracellular levels of dynamin with the formation of neurites in rat hippocampal neurons and neuroblastoma N1E-115 cells in vitro. Quantitative Western and Northern blot analyses show that dynamin levels increase during neurite formation in both the hippocampal neurons and N1E-115 cells and decrease in N1E-115 cells during serum-induced neurite retraction. Furthermore, using anti-sense technology, we investigated the effect of decreased intracellular levels of dynamin on neurite formation in cultured embryonic hippocampal neurons. Antisense oligonucleotides against sequences surrounding the initiation codon of the rat brain dynamin gene (D100) reduce the intracellular levels of dynamin by approximately 90% and impair the formation of the minor and axon-like processes in a dose- dependent manner. Taken together, these results suggest that dynamin-mediated processes are necessary for normal neuronal morphogenesis.