unc7

UNC-7 is a gene in Caenorhabditis elegans that encodes innexin-7, a member of the innexin family of gap junction proteins. Innexins are the invertebrate counterparts of vertebrate connexins and assemble to form gap junction channels that electrically couple adjacent cells. In the C. elegans nervous system, UNC-7 participates in the formation of electrical synapses, often in partnership with UNC-9. Channels formed by UNC-7 and UNC-9 can be heterotypic, contributing to specific electrical connectivity patterns that support rapid neuronal communication.

The UNC-7 protein is expressed in multiple neurons throughout the C. elegans nervous system, and potentially in other tissues. Like other innexins, UNC-7 proteins contain four transmembrane segments with cytoplasmic N- and C- termini, and it exists in several isoforms generated by alternative promoters and splicing. This molecular diversity is thought to contribute to the assembly and regulation of distinct gap junction channels in different cell types.

Genetic studies show that loss of UNC-7 disrupts intercellular dye coupling and reduces electrical coupling between neurons, leading to locomotor and circuit coordination defects. Rescue experiments indicate that UNC-7 functions cell-autonomously in specific neurons to restore proper electrical synapse formation and function. These findings position UNC-7 as a key component of the gap junction network underlying nervous system communication in C. elegans.

UNC-7 serves as a model for understanding how innexin-based gap junctions establish electrical connectivity in invertebrate nervous systems and provides comparative insight into the evolution of intercellular communication.

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