Drosophila Groucho (Gro) is the founding member of a family of metazoan 
corepressors. Gro mediates repression through interactions with a myriad of 
DNA-binding repressor proteins to direct the silencing of genes involved in many 
developmental processes, including neurogenesis and patterning of the main body 
axis, as well as receptor tyrosine kinase/Ras/MAPK, Notch, Wingless (Wg)/Wnt, 
and Decapentaplegic (Dpp) signaling. Gro mediates repression by multiple 
molecular mechanisms, depending on the regulatory context. Because Gro is a 
broadly expressed nuclear factor, whereas its repressor partners display 
restricted temporal and spatial distribution, it was presumed that this 
corepressor played permissive rather than instructive roles in development. 
However, a wide range of studies demonstrates that this is not the case. Gro can 
sense and integrate many cellular inputs to modulate the expression of variety 
of genes, making it a versatile corepressor with crucial instructive roles in 
development and signaling.