Research Interests
Tumor Biology, Development, Stem Cells, Hematopoiesis, Immune Function
Research Techniques: In vivo and in vitro models of hematopoiesis, transformation and immunity, retroviral transduction, bone marrow transplantation, ES cell culture and differentiation, cDNA cloning, cell sorting, video microscopy, knockout and RNAi technology, ChIP-Seq and global transcription analysis
Description of Research
A major area of interest of this laboratory is understanding the processes that lead to the development and differentiation of mature hematopoietic cells from a single hematopoietic stem cell. We are particularly interested in studying the processes that perturb these normal processes and cause leukemia. A primary focus of the laboratory is the role that Notch proteins play in regulating hematopoietic cell fate decisions and cancer. Notch proteins are a conserved family of receptors that regulate cell fate decisions in organisms ranging from Drosophila to humans. Using a variety of in vitro and in vivo approaches, we have shown that Notch proteins are key regulators of multiple hematopoietic cell fates. These include establishment of the T cell lineage and helper type 2 T cells. We are presently undertaking studies to identify the signaling pathways that control these and other cell fate decisions in hematopoiesis. In addition to their role in normal hematopoiesis, dysregulation of Notch signaling is a cause of human leukemia. We have developed a mouse model of Notch-related leukemia and are using this to study the signaling pathways that lead to oncogenic transformation. Using gene array and bioinformatics approaches, we have identified several direct transcriptional targets of Notch signaling that appear to mediate its effects in normal development and leukemia. In addition, we are developing and testing ways to block Notch signaling that may be useful in treating leukemia and other Notch-dependent diseases.
Rotation Projects for 2010
1. Characterization of Notch transcriptional targets in hematopoiesis and leukemia. This project will characterize potential direct transcriptional targets of Notch signaling that we have identified in a microarray screen. The project will involve verifying that these are direct transcriptional targets using chromatin immunoprecipitation (ChIP), EMSA, and reporter assays and then testing whether these targets are functionally important using retroviral transduction, apoptosis, proliferation, and differentiation in both primary and established cell lines.
2. Identification of genes that potentiate Notch transforming activity. We have induced a number of Notch T cell leukemias using retroviruses that express activated forms of Notch1. The retroviral vectors also contain enhancer elements that can activate transcription of genes in the vicinity of their integration site. We have established techniques to rapidly clone the genes that are activated by retroviral vector integration and will use both in vitro and in vivo assays to determine if they synergize with Notch to induce leukemia.
3. We have identified Tribbles as a novel oncogene in acute myelogenous leukemia. Very little is know about Tribbles function. This project will use biochemical and functional assays to determine the function of Tribbles in leukemia and normal hematopoietic development.
Lab personnel:
Will Bailis, Graduate Student
Claudia Lanauze, Research Specialist
Dawson Gerhardt, Graduate Student
Brandon Kremer, Postdoctoral Fellow
Caitlin O'Neill, Administrative Assistant
Yumi Ohtani, Senior Research Investigator
Kosta Pajcini, Postdoctoral Fellow
Kelly Proimos, Graduate Student
Sarah Stein, Postdoctoral Fellow
Lanwei Xu, Research Specialist/Lab Manager
Shuqian Yu, Research Specialist
Selected Publications
Liu H., Chi W.S., Chiang M.Y., Arnett K.L., Xu L., Shestova O., Wang H., Li Y.M., Bhandoola A., Aster J.C., Blacklow S.C., Pear W.S.: Notch dimerization is required for leukemogenesis and T cell development. Genes Dev. 24: 2395-2407, 2010.
Dedhia P.H., Keeshan K., Uljon S., Xu L., Vega M.E., Shestova O., Zaks-Zilberman M., Romany C., Blacklow S.C., Pear W.S.: Differential ability of Tribbles family members to promote degradation of C/EBP{alpha} and induce acute myelogenous leukemia. Blood 116: 1321-8, 2010.
Yashiro-Ohtani Y., He Y., Ohtani T., Jones M.E., Shestova O., Xu L., Fang T.C., Chiang M.Y., Intlekofer A.M., Blacklow S.C., Zhuang Y., Pear W.S.: Pre-TCR signaling inactivates Notch1transcription by antagonizing E2A. Genes Dev. 23: 1665-76, 2009.
Chiang M.Y., Xu L., Shestova O., Histen G., L’Heureux S., Romany C., Childs M.E., Gimotty P.A., Aster J.C., Pear W.S.: Leukemia-associated Notch1 alleles are weak tumor initiators but accelerate K-ras-initiated leukemia. J Clin Invest. 118: 3181-94, 2008.
Maillard I., Koch U., Dumortier A., Shestova O., Xu L., Sai H., Pross S.E., Aster J.C., Bhandoola A., Radtke F., Pear W.S.: Canonical Notch signaling is dispensable for the maintenance of adult hematopoietic stem cells. Cell Stem Cell 2: 356-66, 2008.
Aster J.C., Pear W.S., Blacklow S.C.: Notch signaling in leukemia. Annu Rev Pathol. 3: 587-613, 2008.
Fang T.C., Ohtani Y., Del Bianco C., Knoblock D., Blacklow S.C., Pear W.S.: Notch directly regulates Gata3 expression during T helper 2 cell differentiation. Immunity 27: 100-10, 2007.
Keeshan K., He Y., Wouters B.J., Shestova O., Xu L., Sai H., Rodriguez C., Maillard I., Tobias J.W., Valk P., Carroll M., Aster J.C., Delwel R., Pear W.S.: Tribbles homologue 2 (Trib2) inactivates C/EBPalpha and causes acute myelogenous leukemia. Cancer Cell 10: 401-11, 2006.
Weng A.P., Millholland J.M., Yashiro-Ohtani Y., Arcangeli M.L., Lau A., Wai C., del Bianco C., Rodriguez C.G., Sai H., Tobias J., Li Y., Wolfe M.S., Shachaf C., Felsher D., Blacklow S.C., Pear W.S.*, Aster J.C.*: c-Myc is an important direct target of Notch1 in T cell acute lymphoblastic leukemia/lymphoma. Genes Dev. 20: 2096-109, 2006 Notes: *corresponding authors.
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Last updated: 08/02/2013
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