Cell lineage decisions during development require strict gene regulation by complex networks of multiple transcription factors and collaborating factors. During fate decisions, key transcription factors (TFs) drive precursors into one lineage while inactivating alternative fate genes. Silenced states of a subset of alternativ fate genes are heritably maintained through epigenetic silencing. Epigenetic silencing is globally important for normal cell development and commonly altered in many types of cancers. Establishment of epigenetic silencing involves recruitment of enzyme activities mediating repressive histone methylation and DNA methylation. These enzyme activities are thought to be delivered by specific sets of TFs in a locus- specific manner. However, the mechanisms by which these TFs drive cel fate decisions and then establish epigenetic silencing are not completely understood. In this proposal, we will study crosstalk between key TFs driving T cell lineage choices and epigenetic modifiers that ultimately establish cell lineage identities. T lymphocyte development is an excellent system to tackle these questions because of our strong background knowledge on developmental processes and requirements for TFs. Specifically, we will study functions of Runx transcription factors in gene repression in the context of fate decisions and epigenetic silencing of alternative fate genes. Our efforts will be focused on study of functional collaborations between Runx proteins and their interacting factors that drive and stabilize the fate choice processes. Because Runx proteins are involved in normal development of many cell types, and their functions are frequently altered in leukemia, knowledge obtained through our study of Runx-mediated genetic and epigenetic regulation during T cell development would provide substantial insights into stable gene regulation mechanisms widely used in many cell types as well as altered genetic programs causing cancers.

Public Health Relevance

Diverse cell types are continuously generated from stem/progenitor cells to maintain functional cell compartments. During cell differentiation, a specific set of genes is turned-on or -off by transcription factors, and these distinct states of gene expression are stably maintained. In this study, I propose to investigate the gene regulatory mechanisms that are critical for maintaining cell type diversity in animals and humans.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
4R01AI097244-05
Application #
9116755
Study Section
Cellular and Molecular Immunology - B Study Section (CMIB)
Program Officer
Prabhudas, Mercy R
Project Start
2012-09-24
Project End
2017-08-31
Budget Start
2016-09-01
Budget End
2017-08-31
Support Year
5
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Washington University
Department
Pathology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Ebihara, Takashi; Song, Christina; Ryu, Stacy H et al. (2015) Runx3 specifies lineage commitment of innate lymphoid cells. Nat Immunol 16:1124-33
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