This family consists of several conserved novel zinc finger domains found in the eukaryotic proteins Nanos and Xcat-2. In Drosophila melanogaster, Nanos functions as a localized determinant of posterior pattern. Nanos RNA is localized to the posterior pole of the maturing egg cell and encodes a protein that emanates from this localized source. Nanos acts as a translational repressor and thereby establishes a gradient of the morphogen Hunchback. Xcat-2 is found in the vegetal cortical region and is inherited by the vegetal blasomeres during development, and is degraded very early in development. The localized and maternally restricted expression of Xcat-2 RNA suggests a role for its protein in setting up regional differences in gene expression that occur early in development.