Expression and Function of c-mos in Mammalian Germ Cells

Publisher Summary This chapter discusses the expression and function of c-mos in mammalian germ cells. The c-mos proto-oncogene is unique in being specifically expressed in male and female germ cells where it appears to play a central role in regulating the meiotic cell cycle. In somatic cells, c-mos are either silent or possibly expressed at very low levels, indicating that expression of this proto-oncogene is subject to stringent tissue-specific regulation. The chapter identifies two distinct regulatory elements that activate c-mos transcription in oocytes and repress its transcription in somatic cells. C-mos appears to play a unique role in germ cells, so studies of its expression and function offer the promise of novel insights into the mechanisms that control germ cell development and the meiotic cell cycle. The proteins encoded by most proto-oncogenes are normally expressed in a variety of differentiated cell types, where they generally function as components of signaling pathways that regulate cell growth and differentiation. The c-mos gene also encodes a protein-serine/threonine kinase (Mos). Both the regulation and function of c-mos thus pose important issues with respect to understanding the molecular mechanisms that control mammalian development.