The goals of this project are to understand how the processes of proliferation and differentiation are controlled and coordinated in blood cells and how leukemic transformation perturbs these processes. Much progress has been made in identifying the transcription factors that control blood cell development, but there is still much to be learned about how they interact functionally with each other. We also know very little about how these transcription factors regulate cell proliferation and interact with the molecules that control the cell cycle. Understanding these mechanisms and relationships will lead to new insights into how cells control and coordinate the proliferation and differentiation programs. It also will provide opportunities for development of new therapeutic approaches based on the concept of stimulating leukemia cells to resume differentiation and enter terminal cell division. Work carried out during the current grant period shows that two key transcription factors, PU. 1 and GATA-1, that control blood lineage determination, mutually antagonize each other. We showed this mutual antagonism is important for normal blood cell development. We also found that PU.1-mediated repression of GATA-1 requires the corepressor and cell cycle regulator Rb. PU.1 and Rb cooperate to block erythroid differentiation in murine erythroleukemia cells. We now propose to understand the mechanism(s) by which PU.1 and Rb cooperate to repress GATA-1 and inhibit the erythroid program in immature erythroid cells and in myeloid cells. We also propose to determine the role of Rb and PU.1-mediated erythroleukemia in mice. Other studies from our laboratory indicate that PU.1 also cooperates with a cyclin D-dependent kinase, CDK6, to block erythroid differentiation and to stimulate proliferation in immature erythroid cells. We found that CDK6 can phosphorylate PU.1. We also found that, like PU.1, CDK6 can block erythroid differentiation in murine erythroleukemia cells. We now propose to understand how CDK6 phosphorylation of PU.1 controls PU.1 activity and/or metabolism. We also will test whether, like PU.1, CDK6 can promote leukemia in mice.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL078381-33
Application #
7260371
Study Section
Hematopoiesis Study Section (HP)
Program Officer
Chang, Henry
Project Start
1977-05-01
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2008-06-30
Support Year
33
Fiscal Year
2007
Total Cost
$412,519
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
110521739
City
Bronx
State
NY
Country
United States
Zip Code
10461
Wontakal, Sandeep N; Guo, Xingyi; Smith, Cameron et al. (2012) A core erythroid transcriptional network is repressed by a master regulator of myelo-lymphoid differentiation. Proc Natl Acad Sci U S A 109:3832-7
Wontakal, Sandeep N; Guo, Xingyi; Will, Britta et al. (2011) A large gene network in immature erythroid cells is controlled by the myeloid and B cell transcriptional regulator PU.1. PLoS Genet 7:e1001392
Choe, Kevin S; Ujhelly, Olga; Wontakal, Sandeep N et al. (2010) PU.1 directly regulates cdk6 gene expression, linking the cell proliferation and differentiation programs in erythroid cells. J Biol Chem 285:3044-52
Papetti, Michael; Wontakal, Sandeep N; Stopka, Tomas et al. (2010) GATA-1 directly regulates p21 gene expression during erythroid differentiation. Cell Cycle 9:1972-80
Vargova, Jarmila; Vargova, Karina; Skoultchi, Arthur I et al. (2009) Nuclear localization of ISWI ATPase Smarca5 (Snf2h) in mouse. Front Biosci (Elite Ed) 1:553-9
Burda, Pavel; Curik, Nikola; Kokavec, Juraj et al. (2009) PU.1 activation relieves GATA-1-mediated repression of Cebpa and Cbfb during leukemia differentiation. Mol Cancer Res 7:1693-703
Papetti, Michael; Skoultchi, Arthur I (2007) Reprogramming leukemia cells to terminal differentiation and growth arrest by RNA interference of PU.1. Mol Cancer Res 5:1053-62
Yu, Yung-Luen; Chiang, Yun-Jung; Chen, Yu-Chun et al. (2005) MAPK-mediated phosphorylation of GATA-1 promotes Bcl-XL expression and cell survival. J Biol Chem 280:29533-42
Stopka, Tomas; Amanatullah, Derek F; Papetti, Michael et al. (2005) PU.1 inhibits the erythroid program by binding to GATA-1 on DNA and creating a repressive chromatin structure. EMBO J 24:3712-23