A SPERM-SUPPLIED FACTOR REQUIRED FOR EMBRYOGENESIS IN C-ELEGANS

The paternal-effect embryonic-lethal gene, spe-11, is required for nor mal development of early C. elegans embryos, Spe-11 embryos fail to co mplete meiosis, form a weak eggshell, fail to orient properly the firs t mitotic spindle, and fail to undergo cytokinesis, Here we report clo ning and sequencing of the spe-11 gene, which encodes a novel protein. As predicted by the paternal-effect mutant phenotype, the gene is exp ressed during spermatogenesis but is not detectable in females undergo ing oogenesis, and the protein is present in mature sperm. To investig ate whether SPE-11's essential function is during spermatogenesis or w hether sperm-delivered SPE-11 functions in the newly fertilized embryo , we engineered animals to supply SPE-11 to the embryo through the ooc yte rather than through the sperm, We found that maternal expression i s sufficient for embryonic viability, This result demonstrates that SP E-11 is not required during spermatogenesis, and suggests that SPE-11 is a sperm-supplied factor that participates directly in development o f the early embryo, In contrast to the many known maternal factors req uired for embryogenesis, SPE-11 is the first paternally contributed fa ctor to be genetically identified and molecularly characterized.