The Rhox genes

Abstract

Homeobox genes encode transcription factors that have crucial roles in embryogenesis. A recently discovered set of homeobox genes – theRhoxgenes – are expressed during both embryogenesis and in adult reproductive tissues. The 33 known mouseRhoxgenes are clustered together in a single region on the X chromosome, while likely descendents of the primodialRhoxcluster,ArxandEsx1, have moved to other positions on the X chromosome. Here, we summarize what is known about the regulation and function ofRhoxcluster andRhox-related genes during embryogenesis and gametogenesis. The founding member of theRhoxgene cluster –Rhox5(previously known asPem) – has been studied in the most depth and thus is the focus of this review. We also discuss the unusually rapid evolution of theRhoxgene cluster.