Presenter(s): Elisa Trujillo
Faculty Mentor(s): Adam Miller & Abagael Lasseigne
Poster 56
Session: Sciences
In order to initiate synaptogenesis two cells must come together and undergo intracellular communication; both can be done through a protein with cell adhesive properties. At chemical synapses, extracellular cell adhesion molecules allow two neurons to communicate in order to recruit compatible pre- and postsynaptic machinery. By contrast little is known about electrical synapses, where gap junction channels physically couple neurons. Transmembrane gap junction proteins at the electrical synapse, Connexins, have adhesive properties. We hypothesized that Connexins are required to initiate electrical synapse formation. To investigate this we created Connexin mutant animals and assessed whether or not a highly stereotyped electrical circuit containing Mauthner neurons was still morphologically normal. We used the localization of the required scaffolding protein, Tjp1b, as an indicator for electrical synapse specification. Connexin proteins are co-dependent; without one Connexin the other is unable to localize to the synapse. I tested the requirement of the pre- and postsynaptically required Connexin proteins for normal neuron morphology and Tjp1b localization by selecting fish with green fluorescent protein (GFP) positive Mauthner neurons and immunostaining zebrafish larvae for Tjp1b, and GFP in animals with non-functional Connexin proteins. Despite the loss of Connexins, Tjp1b still localized at the potential electrical synapse site and the morphology of the Mauthner neuron remained normal. Thus, Connexins do not appear to be the proteins responsible for electrical synapse initiation. My future work will aim to identify the protein with cell adhesion properties necessary for electrical synaptogenesis.