Mice lacking the Nkx6.2 (Gtx) homeodomain transcription factor develop andreproduce normally

The Nkx homeobox genes are expressed in a variety of developing tissues and have been implicated in controlling tissue patterning and cell differentia tion. Expression of Nkx6.2 (Gtx) was previously observed in the embryonic n eural tube, testis, and differentiating oligodendrocytes. To investigate th e role of Nkx6.2 in the control of cell specification and differentiation, we generated mice with null mutations in Nkx6.2 using the standard gene tar geting approach. Null mutant mice were viable and fertile without apparent histological and immunohistochemical changes in the central nervous systems and testis. The absence of detectable phenotypes suggests a redundant func tion of Nkx6.2 in mouse development.