Undifferentiated neural precursor cells can be derived from embryonic stem cells or reprogrammed somatic (iPS) cells in unlimited quantities, have broad differentiation potential, can be modified by genetic engineering or clonally selected for particular properties and, for iPS cells, can be patient-matched to avoid immunological incompatibilities. Therefore, these cells are of high significance for in vitro modeling of human neurological diseases and for developing transplantation-based therapies to replace or stimulate repair of damaged tissue. Given the broad utility of these cells, we know surprisingly little about cell intrinsic regulatory networks that direct the initial acquisition of a neural fate and that maintain neural precursors in an undifferentiated state. This significantly limits our understanding of neural development and hampers efforts to compare and manipulate neural precursor cells derived from different starting cell sources or protocols. During vertebrate embryogenesis, Geminin and the Zic family of zinc finger transcription factors control the earliest cell intrinsic responses to neural induction and have essential roles in initial neural specification and maintenance of the undifferentiated state. Mutational analyses of these transcription factors supports their central roles in development and contribution to human disease: complete loss of Geminin results in early embryonic lethality in mice, while Zic1-4 mutations in humans cause a range of embryonic and nervous system malformations and neurological disorders. However, regulatory networks and mechanisms through which these transcription factors act remain largely unknown. Here, we will elucidate transcriptional programs and direct targets that they control at a genome-wide level and will use these data to construct regulatory networks underlying neural fate acquisition. We will test the hypothesis that Geminin is a central regulator of neural versus non-neural fate choice, through interactions with distinct epigenetic regulatory complexes. This work will define epigenetic regulatory mechanisms that direct the earliest aspects of embryonic cell fate acquisition. We will pursue the following Specific Aims: 1. Determine mechanisms by which Geminin activates neural gene expression to promote neural cell fate, 2. Define and compare the transcriptional regulatory networks through which the Zic transcription factors and Geminin control neural specification, and 3. Test the hypothesis that Geminin acts cooperatively with Polycomb to repress non-neural, mesendodermal gene expression during early fate acquisition of embryonic cells. Together, this work will define the regulatory networks controlling initial neural fate acquisition will identify new neural regulatory activities and modes of regulation, and will determine mechanisms through which several epigenetic regulators centrally control cell state and developmental potential during early fate acquisition. These data will fill a fundamental gap in our understanding of early cell fate acquisition. They will inform our understanding of birth defects and provide an essential foundation for manipulating these regulatory networks to control neural cell specification in many biological contexts.

Public Health Relevance

This work will define regulatory networks that direct embryonic stem cells and reprogrammed somatic (e.g. skin) cells to form neural precursor cells that can differentiate into many different cell types in the central nervous system. This information provides a central foundation for effectively generating these cells and making molecular comparisons between neural precursors created using different cell sources or procedures. These cells have significant medical value, both for human therapies that replace or stimulate repair of damaged and diseased neural tissue and for studying the basis of and testing treatments for neurological diseases.!

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM066815-10A1
Application #
8436889
Study Section
Neurogenesis and Cell Fate Study Section (NCF)
Program Officer
Haynes, Susan R
Project Start
2003-01-01
Project End
2016-12-31
Budget Start
2013-01-18
Budget End
2013-12-31
Support Year
10
Fiscal Year
2013
Total Cost
$354,160
Indirect Cost
$121,160
Name
Washington University
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Siles, Laura; Sanchez-Tillo, Ester; Lim, Jong-Won et al. (2013) ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. Mol Cell Biol 33:1368-82
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Lim, Jong-Won; Hummert, Pamela; Mills, Jason C et al. (2011) Geminin cooperates with Polycomb to restrain multi-lineage commitment in the early embryo. Development 138:33-44
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