Specificity of Gap Junction Connections in C. elegans Nervous System

Abstract

Gap junctions are channel proteins that facilitate communication between cells through the diffusion of small molecules. A gap junction is formed when two hemichannels (one from each cell) come together. Each hemichannel is composed of six protein subunits which can be the same or different (in vertebrates they are termed connexins and pannexins, in invertebrates they are called innexins). Researchers are still investigating the mechanisms involved in the formation of gap junctions and why cells form them with only some of their neighbors. Subunit composition may be one way that cells regulate the connections they form in this manner, but researchers are led to believe there are more factors involved. In the nematode Caenorhabditis elegans, unc-7 and unc-9 are innexins expressed in most motor neurons of the ventral nerve cord. It has been determined that unc-7 and unc-9 interact with each other to form a gap junction between the AVB interneurons and B class motor neurons. The purpose of this study is to determine if there are other factors that affect the formation of the unc-7 and unc-9 gap junction pair. This will be done by developing a strain of C. elegans that has the UNC-7 protein tagged with a green fluorescent protein which allows the UNC-7 to be visualized in vivo. Genetic mutanegenisis will then be performed and worms will be screened for a disruption in the stereotypical location of UNC-7. If a disruption is observed, the mutated gene responsible can then be identified.