The C-elegans zyg-1 gene encodes a regulator of centrosome duplication with distinct maternal and paternal roles in the embryo

Centrosome duplication is a critical step in assembly of the bipolar mitoti c spindle, but the molecular mechanisms regulating this process during the cell cycle and during animal development are poorly understood. Here, we re port that the zyg-1 gene of Caenorhabditis elegans is an essential regulato r of centrosome duplication. ZYG-1 is a protein kinase specifically require d for daughter centriole formation that localizes transiently to centrosome s and acts at least one cell cycle prior to each spindle assembly event. In the embryo, ZYG-1 participates in a unique regulatory scheme whereby pater nal ZYG-1 regulates duplication and bipolar spindle assembly during the fir st cell cycle, and maternal ZYG-1 regulates these processes thereafter. ZYG -1 is therefore a key molecular component of the centrosome/centriole dupli cation process.