Molecular biology of Clostridial toxins: expression of mRNAs encoding tetanus and botulinum neurotoxins in Aplysia neurons

mRNAs encoding the light chain of tetanus and botulinum neurotoxins were transcribed, in vitro, from the cloned and specifically truncated genes of Clostridium tetani and Clostridium botulinum, respectively, and injected into presynaptic identified cholinergic neurons of the buccal ganglia of Aplysia californica. The size of the current response measured in the voltage clamped postsynaptic neuron was taken as indicator of the quantity of acetylcholine released. Depression of neurotransmitter release similar to that observed when native light chains of the two toxins were injected but needing an additional delay of 30 to 40 minutes, demonstrated a successful expression of a foreign mRNA injected into a neuron in situ.