Previous Article | Next Article 
Molecular and Cellular Biology, August 2009, p. 4376-4393, Vol. 29, No. 16
0270-7306/09/$08.00+0 doi:10.1128/MCB.01330-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Increased c-Jun Expression and Reduced GATA2 Expression Promote Aberrant Monocytic Differentiation Induced by Activating PTPN11 Mutants
,
Zhenyun Yang,1,2
Takako Kondo,3
Cara S. Voorhorst,1,2
Sarah C. Nabinger,2,4
Leila Ndong,2
Fuqin Yin,1,2
Edward M. Chan,7
Menggang Yu,6
Oliver Würstlin,8
Christian P. Kratz,8
Charlotte M. Niemeyer,8
Christian Flotho,8
Eri Hashino,3,5 and
Rebecca J. Chan1,2,4*
Department of Pediatrics,1 Herman B Wells Center for Pediatric Research,2 Department of Otolaryngology,3 Department of Medical & Molecular Genetics,4 Department of Pharmacology and Toxicology,5 Department of Medicine, Division of Biostatistics, Indiana University School of Medicine, Indianapolis, Indiana,6 Eli Lilly and Company, Indianapolis, Indiana,7 Department of Pediatrics and Adolescent Medicine, University of Freiburg, Freiburg, Germany8
Received 22 August 2008/ Returned for modification 29 October 2008/ Accepted 21 May 2009
Juvenile myelomonocytic leukemia (JMML) is characterized by myelomonocytic cell overproduction and commonly bears activating mutations in PTPN11. Murine hematopoietic progenitors expressing activating Shp2 undergo myelomonocytic differentiation, despite being subjected to conditions that normally support only mast cells. Evaluation of hematopoietic-specific transcription factor expression indicates reduced GATA2 and elevated c-Jun in mutant Shp2-expressing progenitors. We hypothesized that mutant Shp2-induced Ras hyperactivation promotes c-Jun phosphorylation and constitutive c-Jun expression, permitting, as a coactivator of PU.1, excessive monocytic differentiation and reduced GATA2. Hematopoietic progenitors expressing activating Shp2 demonstrate enhanced macrophage CFU (CFU-M) compared to that of wild-type Shp2-expressing cells. Treatment with the JNK inhibitor SP600125 or cotransduction with GATA2 normalizes activating Shp2-generated CFU-M. However, cotransduction of 
GATA2 (lacking the C-terminal zinc finger, needed to bind PU.1) fails to normalize CFU-M. NIH 3T3 cells expressing Shp2E76K produce higher levels of luciferase expression directed by the macrophage colony-stimulating factor receptor (MCSFR) promoter, which utilizes c-Jun as a coactivator of PU.1. Coimmunoprecipitation demonstrates increased c-Jun-PU.1 complexes in mutant Shp2-expressing hematopoietic progenitors, while chromatin immunoprecipitation demonstrates increased c-Jun binding to the c-Jun promoter and an increased c-Jun-PU.1 complex at the Mcsfr promoter. Furthermore, JMML progenitors express higher levels of c-JUN than healthy controls, substantiating the disease relevance of these mechanistic findings.
* Corresponding author. Mailing address: Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Cancer Research Institute, 1044 W. Walnut Street, R4-402, Indianapolis, IN 46202. Phone: (317) 278-2807. Fax: (317) 274-8679. E-mail: rchan{at}iupui.edu
Published ahead of print on 15 June 2009.
Supplemental material for this article may be found at http://mcb.asm.org/.
Molecular and Cellular Biology, August 2009, p. 4376-4393, Vol. 29, No. 16
0270-7306/09/$08.00+0 doi:10.1128/MCB.01330-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»