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Runx1 regulation of Pu.1 corepressor/coactivator exchange identifies specific molecular targets for leukemia differentiation therapy.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2014 May 23; Vol. 289 (21), pp. 14881-95. Date of Electronic Publication: 2014 Apr 02. - Publication Year :
- 2014
-
Abstract
- Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy.<br /> (© 2014 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Subjects :
- Animals
Blotting, Western
Cells, Cultured
Chromatin Immunoprecipitation
Co-Repressor Proteins metabolism
Core Binding Factor Alpha 2 Subunit metabolism
Gene Expression Profiling
HEK293 Cells
Humans
Leukemia genetics
Leukemia metabolism
Leukemia pathology
Macrophages metabolism
Mice
Mice, Knockout
Mutation
Oligonucleotide Array Sequence Analysis
Protein Binding
Proto-Oncogene Proteins metabolism
Tandem Mass Spectrometry
Trans-Activators metabolism
Tumor Cells, Cultured
Cell Differentiation genetics
Co-Repressor Proteins genetics
Core Binding Factor Alpha 2 Subunit genetics
Proto-Oncogene Proteins genetics
Trans-Activators genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 289
- Issue :
- 21
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 24695740
- Full Text :
- https://doi.org/10.1074/jbc.M114.562447