Mechanistic understanding of cell fate decisions towards neuronal lineage
Abstract/Contents
- Abstract
- Direct lineage reprogramming is a promising approach for human disease modeling and regenerative medicine with poorly understood mechanisms. Here we reveal a hierarchical mechanism in the direct conversion of fibroblasts into induced neuronal (iN) cells mediated by the transcription factors Ascl1, Brn2, and Myt1l. Ascl1 acts as an "on target" pioneer factor by immediately occupying most cognate genomic sites in fibroblasts. In contrast, Brn2 and Myt1l do not access fibroblast chromatin productively on their own; instead Ascl1 recruits Brn2 to Ascl1 sites genome-wide. A unique trivalent chromatin signature in the host cells predicts the permissiveness for Ascl1 pioneering activity among different cell types. Finally, we identified Zfp238 as a key Ascl1 target gene that can partially substitute for Ascl1 during iN cell reprogramming. Thus, precise match between pioneer factor and the chromatin context at key target genes is determinative for trans-differentiation to neurons and likely other cell types. Long noncoding RNAs (lncRNAs) are potential regulators of cell fate but often ignored in human genetics. We describe an integrative strategy to identify lncRNAs mutated in neurodevelopmental disorders. Direct reprogramming of fibroblasts to induced neuronal (iN) cells identified a family of lncRNAs that are largely brain-specific, and suffice to promote neurogenesis or neuronal maturation in vitro. Copy number variation morbidity map of a large cohort of children with autism spectrum disorder or intellectual disability vs. healthy controls revealed recurrent focal genomic mutations affecting five iN lncRNA loci, and thus potentially contributing to pathogenesis. Lnc-NR2F1 is an evolutionarily conserved lncRNA that promotes iN cell maturation, and is disrupted by a t(5:12) chromosomal translocation in a family manifesting neurodevelopmental symptoms. Lnc-NR2F1 transcriptionally regulates an autism gene network controlling neuronal and axonogenesis pathways. Thus, integration of direct lineage reprogramming and human genetics is a promising approach for discovering lncRNAs involved in human diseases. Overall, this thesis unveils molecular mechanisms of direct lineage reprogramming into neurons by elucidating the role of transcription factors and lncRNAs. Insights from these studies enable better understanding of direct cell conversion processes and sheds light into disrupted pathways in neurological disease.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Wapinski, Orly Liel |
|---|---|
| Associated with | Stanford University, Cancer Biology Program. |
| Primary advisor | Chang, Howard |
| Thesis advisor | Chang, Howard |
| Thesis advisor | Brunet, Anne, 1972- |
| Thesis advisor | Khavari, Paul A |
| Thesis advisor | Wernig, Marius |
| Advisor | Brunet, Anne, 1972- |
| Advisor | Khavari, Paul A |
| Advisor | Wernig, Marius |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Orly Liel Wapinski. |
|---|---|
| Note | Submitted to the Program in Cancer Biology. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Orly Liel Wapinski
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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