Homeobox genes Gsx1
) are among the earliest transcription factors expressed in neuronal progenitors of the lateral ganglionic eminence (LGE) in the ventral telencephalon. Because no specific phenotype has been described in Gsx1
mutants, it is unclear what role this factor plays in the development of the ventral telencephalon. Gsx1
differentially regulate the maturation of LGE progenitors. Specifically, Gsx2
maintains LGE progenitors in an undifferentiated state, whereas Gsx1
promotes progenitor maturation and the acquisition of neuronal phenotypes, at least in part, through the down-regulation of Gsx2
. These unique results indicate that the two closely related Gsx
genes similarly regulate LGE patterning but oppositely control the balance between proliferation and differentiation in the neuronal progenitor pool.