The MurineFem1Gene Family: Homologs of theCaenorhabditis elegansSex-Determination Protein FEM-1

Abstract

The pathway controlling sex determination in the nematode Caenorhabditis elegans is a model for the genetic control of cell-fate determination. We report here the cloning and characterization of a new mouse gene family with homology to FEM-1, a signal-transducing regulator in the C. elegans sex-determination pathway. This gene family consists of two known members, designated Fem1a and Fem1b. The highest degree of homology between the two mouse proteins and the nematode protein is in a domain that encodes seven sequential ANK repeats. The Fem1a gene localizes to chromosome 17 and is highly expressed in adult heart and skeletal muscle. The Fem1b gene localizes to chromosome 9 and is highly expressed in adult testis. Both genes are expressed during embryogenesis. The existence of FEM-1 homologs in the mouse raises the possibility that evolutionary conservation of ancient FEM-1 signaling interactions may play a role in vertebrate cell-fate determination.