Constitutive Expression of PU.1 in Fetal Hematopoietic Progenitors Blocks T Cell Development at the Pro-T Cell Stage
Abstract
The essential hematopoietic transcription factor PU.1 is expressed in multipotent thymic precursors but downregulated during T lineage commitment. The significance of PU.1 downregulation was tested using retroviral vectors to force hematopoietic precursors to maintain PU.1 expression during differentiation in fetal thymic organ culture. PU.1 reduced thymocyte expansion and blocked development at the pro-T cell stage. PU.1-expressing cells could be rescued by switching to conditions permissive for macrophage development; thus, the inhibition depends on both lineage and developmental stage. An intact DNA binding domain was required for these effects. PU.1 expression can downregulate pre-Tα, Rag-1, and Rag-2 in a dose-dependent manner, and higher PU.1 levels induce Mac-1 and Id-2. Thus, downregulation of PU.1 is specifically required for progression in the T cell lineage.
Additional Information
© 2002 Cell Press. Received 6 July 2001, Revised 8 January 2002, Available online 7 March 2002. We gratefully acknowledge the gift of the pLZRS vector by Hergen Spits (Netherlands Cancer Institute), Garry Nolan (Stanford University), and David Rawlings (UCLA), the SCID.adh cells from Michael Carleton and David Wiest (Fox Chase Cancer Center), and the BHK-MKL cells from Schickwann Tsai (University of Washington). We express gratitude to Hiroshi Kawamoto and Yoshimoto Katsura (Kyoto University) for the generous advice on HOS-FTOC cultures. We also thank Shirley Pease, Bruce Kennedy, and Eva Borucka of the Caltech Transgenic Animal Facility for timed matings, Ali Lotfizadeh for assistance in some Western blotting experiments, Kevin Tse for assistance with the SCID.adh cells, and Rochelle Diamond and Pat Koen of the Caltech Flow Cytometry/Cell Sorting Facility for fluorescence-activated cell sorting. M.K.A., G.H.-H., and A.H.W. have been supported by the Stowers Institute for Medical Research, Kansas City, Missouri. Additional support was provided by National Institutes of Health Grant CA90233 and National Science Foundation Grant MCB-9983129.Additional details
- Eprint ID
- 74168
- Resolver ID
- CaltechAUTHORS:20170208-142853035
- Stowers Institute for Medical Research
- CA90233
- NIH
- MCB-9983129
- NSF
- Created
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2017-02-08Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field