In Nr4a3-/-Nr4a1-/- mice, the expression of PU.1 was not affected, but the transcripts of c-Jun and JunB were significantly down-regulated, indicating that the downregulation of AP-1 transcription factors may contribute to the development of AML in these mice (Mullican et al., 2007). The gene discussed is JUNB; the disease is acute myeloid leukemia.