Mint is a newly identified molecule that mediates signal transduction and modulates chromatin repression. Mint family members contain a highly conserved C-terminus SPOC domain (SpenParalog and OrthologsC-terminal domain) commonly associated with proliferation and related diseases (for example: cancer) due to its role in cell differentiation and apoptosis. In this study, we addressed the SPOC function using a tetracycline-inducible system to express the target domain in Ain V15 embryonic ES cells and bone marrow stem cells from SPOC transenic mice. In vitro differentiation of Ain V15 ES cells as a model of early hematopoietic development, we found expression of SPOC domain induces hematopoietic differentiation via up-regulation of transcription factors Bmp4 and Smad5, which induce the expression of hematopoietic factors Eklf1 and hematopoietic proliferation associated factor Gata2, the SPOC domain also plays the regulation function in the differentiation of hematopoitic progenitor by colony forming Unit (CFU) assays. Further, we determined SPOC expression enhances erythrocyte and granulocyte maturationusing bone marrow cells derived from tiSPOC chimeric mice. Finally, we identified that overexpression of full length Mint in ES cells drive Smad5 and Bmp4 up-regulation under culture conditions, and up-regulation of endogenous Mint when induceshematopoitic differentiation of EML, M1 and WT18 cells. In summary, our study reveals the conserved SPOC domain of Mint protein induces differentiation both in the stages of embryonic stem cells and hematopoietic progenitor cells.
Wiellette, E. L., K. W. Harding, et al. (1999). “spen encodes an RNP motif protein that interacts with Hox pathways to repress the development of head-like sclerites in the Drosophila trunk.” Development 126(23),5373-85.
Chen, F. and I. Rebay (2000). “split ends, a new component of the Drosophila EGF receptor pathway,regulates development of midline glial cells.” CurrBiol10(15), 943-6. doi:10.1016/S0960-9822(00)00625-4
Kolodziej, P. A., L. Y. Jan, et al. (1995). “Mutations that affect the length, fasciculation, or ventral orientation of specific sensory axons in the Drosophila embryo.” Neuron 15(2): 273-86. doi:10.1016/0896-6273(95)90033-0
Tsuji, M., R. Shinkura, et al. (2007). “Msx2-interacting nuclear target protein (Mint) deficiency reveals negative regulation of early thymocyte differentiation by Notch/RBP-J signaling.” ProcNatlAcadSci USA 104(5): 1610-5. doi:10.1073/pnas.0610520104
Newberry, E. P., T. Latifi, et al. (1999). “The RRM domain of MINT, a novel Msx2 binding protein, recognizes and regulates the rat osteocalcin promoter.” Biochemistry 38(33): 10678-90. doi:10.1021/bi990967j
Kyba, M., R. C. Perlingeiro, et al. (2002). “HoxB4 confers definitive lymphoid-myeloid engraftment potential on embryonic stem cell and yolk sac hematopoietic progenitors.” Cell 109(1): 29-37. doi:10.1016/S0092-8674(02)00680-3
Ariyoshi M; Schwabe, J.W.R (2003). “A conserved structural motif reveals the essential transcriptional repression function of Spen proteins and their role in developmental signaling”. Genes & Development 17: 1909-1920. doi:10.1101/gad.266203
Bruno, E., S. K. Horrigan, et al. (1998). “The Smad5 gene is involved in the intracellular signaling pathways that mediate the inhibitory effects of transforming growth factor-beta on human hematopoiesis.” Blood 91(6): 1917-23.
Fuchs, O., O. Simakova, et al. (2002). “Inhibition of Smad5 in human hematopoietic progenitors blocks erythroid differentiation induced by BMP4.” Blood Cells Mol Dis 28(2): 221-33. doi:10.1006/bcmd.2002.0487
Liu, B., Y. Sun, et al. (2003). “Disruption of Smad5 gene leads to enhanced proliferation of highproliferativepotential precursors during embryonic hematopoiesis.” Blood 101(1): 124-33. doi: 10.1182/blood- 2002-02-0398