Figure 7.

Gene expression analysis of bone marrow cells from wild-type, Arid4a^−/−, and Arid4a^−/−Arid4b^+/− mice. A) Reverse transcriptase–polymerase chain reaction was performed to analyze the genes indicated, with Hprt serving as the control gene. Three separate experiments were performed. B) Pathways by which Arid4a and Arid4b might regulate hematopoiesis through control of the Hox and Fox genes. In the scenario shown, Arid4a controls erythropoiesis, possibly by positively regulating Pitx2 and Hoxb6 genes. Arid4a also controls the expression of Hoxb8, whose product blocks differentiation of hematopoietic stem cells and common myeloid progenitors. Control of B lymphopoiesis by Arid4a may be achieved by increasing expression of Hoxb3. Arid4a, together with Arid4b, increases expression of Foxp3, which acts on regulatory T (TR) cells to suppress conventional T (Tc) cells. Foxp3 also functions as a tumor suppressor gene. However, it is unclear whether Foxp3 suppresses leukemia malignancies.