Ptbp2 represses adult-specific splicing to regulate the generation of neuronal precursors in the embryonic brain
- Donny D. Licatalosi1,4,
- Masato Yano1,5,
- John J. Fak1,
- Aldo Mele1,
- Sarah E. Grabinski2,
- Chaolin Zhang1 and
- Robert B. Darnell1,3,6
- 1Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, New York 10065, USA;
- 2Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, USA;
- 3Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065, USA
Abstract
Two polypyrimidine tract RNA-binding proteins (PTBs), one near-ubiquitously expressed (Ptbp1) and another highly tissue-restricted (Ptbp2), regulate RNA in interrelated but incompletely understood ways. Ptbp1, a splicing regulator, is replaced in the brain and differentiated neuronal cell lines by Ptbp2. To define the roles of Ptbp2 in the nervous system, we generated two independent Ptbp2-null strains, unexpectedly revealing that Ptbp2 is expressed in neuronal progenitors and is essential for postnatal survival. A HITS-CLIP (high-throughput sequencing cross-linking immunoprecipitation)-generated map of reproducible Ptbp2–RNA interactions in the developing mouse neocortex, combined with results from splicing-sensitive microarrays, demonstrated that the major action of Ptbp2 is to inhibit adult-specific alternative exons by binding pyrimidine-rich sequences upstream of and/or within them. These regulated exons are present in mRNAs encoding proteins associated with control of cell fate, proliferation, and the actin cytoskeleton, suggesting a role for Ptbp2 in neurogenesis. Indeed, neuronal progenitors in the Ptbp2-null brain exhibited an aberrant polarity and were associated with regions of premature neurogenesis and reduced progenitor pools. Thus, Ptbp2 inhibition of a discrete set of adult neuronal exons underlies early brain development prior to neuronal differentiation and is essential for postnatal survival.
Keywords
- HITS-CLIP
- polypyrimidine tract-binding protein
- RNA-binding map
- alternative splicing
- brain development
- neuronal progenitor
Footnotes
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↵6 Corresponding author
Email darnelr{at}rockefeller.edu
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Supplemental material is available for this article.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.191338.112.
- Received March 10, 2012.
- Accepted May 31, 2012.
- Copyright © 2012 by Cold Spring Harbor Laboratory Press