The C. elegans developmental fusogen EFF-1 mediates homotypic fusion in heterologous cells and in vivo.

During cell-cell fusion, two cells' plasma membranes merge, allowing the cytoplasms to mix and form a syncytium. Little is known about the mechanisms of cell fusion. Here, we asked whether eff-1, shown previously to be essential for fusion in Caenorhabditis elegans, acts directly in the fusion machinery.

EFF-1 is sufficient to initiate and execute tissue-specific cell fusion in C. elegans.

Despite the identification of essential processes in which cell fusion plays spectacular roles such as in fertilization and development of muscle, bone, and placenta, there are no identified proteins that directly mediate developmental cell fusion reactions. C. elegans has recently become among the best-characterized models to use for studying developmental cell fusion.