Prof Tsim has chosen the vertebrate neuromuscular junctions as the model system to study the cellular and molecular events that lead to the formation of synapses during development and regeneration. The post-synaptic specializations, induced by motor neuron, include the expression and aggregation of acetylcholine receptors (AChRs), acetylcholinesterase (AChE) and other synaptic molecules in the muscle cell. Results from our laboratory have indicated that adenosine 5′-triphosphate (ATP), co-released with acetylcholine from the motor neurons, induces the expression of AChR/AChE by activating its receptors, P2Y subtype. Prof Tsim intends to use molecular genetic methods to: (i) determine the role of ATP and P2Y receptors in directing the formation of post-synaptic specializations; (ii) reveal the signaling pathway of P2Y receptor-mediated AChR/AChE gene activation in muscle; (iii) map the transcriptional elements of the catalytic subunit and the collagen-tail (ColQ) subunit of AChE during muscle development.