Engrailed is a transcriptional regulator that has recently been linked to fate determination and survival of midbrain dopaminergic neurons. Engrailed (En) knockout mice have shown Parkinson-like symptoms, and En has also been linked to autism spectrum disorder. The objective of this research is to use drosophila (fruit fly), a simple model system that has identifiable neurons, to investigate the role En plays in regulating neuronal connectivity. Specifically, this research will focus on how En controls synaptic target recognition and identify the downstream effector genes that it regulates. Drosophila models are particularly useful for the discovery of molecular pathways that are directly relevant to human health because most of these pathways have been conserved during evolution. All animals have Engrailed protein, so it is very likely that any molecules that are regulated by it during the process of synapse formation in Drosophila have their counterparts in humans. These molecules may be of great potential importance in neurological diseases, such as Parkinson's or autism.