Proteomic identification of the MYST domain histone acetyltransferase TIP60 (HTATIP) as a co-activator of the myeloid transcription factor C/EBPalpha.
The transcription factor C/EBPalpha (CEBPA) is a key player in granulopoiesis and leukemogenesis. We have previously reported the interaction of C/EBPalpha with other proteins (utilizing mass spectrometry) in transcriptional regulation. In the present study, we characterized the association of the MYST domain histone acetyltransferase Tat-interactive protein (TIP) 60 (HTATIP) with C/EBPalpha. We show in pull-down and co-precipitation experiments that C/EBPalpha and HTATIP interact. A chromatin immunoprecipitation (ChIP) and a confirmatory Re-ChIP assay revealed in vivo occupancy of the C/EBPalpha and GCSF-R promoter by HTATIP. Reporter gene assays showed that HTATIP is a co-activator of C/EBPalpha. The co-activator function of HTATIP is dependent on its intact histone acetyltransferase (HAT) domain and on the C/EBPalpha DNA-binding domain. The resulting balance between histone acetylation and deacetylation at the C/EBPalpha promoter might represent an important mechanism of C/EBPalpha action. We observed a lower expression of HTATIP mRNA in undifferentiated U937 cells compared to retinoic acid-induced differentiated U937 cells, and correlated expression of CEBPA and HTATIP mRNA levels were observed in leukemia samples. These findings point to a functional synergism between C/EBPalpha and HTATIP in myeloid differentiation and suggest that HTATIP might be an important player in leukemogenesis.
Bararia
D
D
Department of Medicine III, University of Munich and Clinical Cooperative Group, HelmholtzZentrum German Research Center for Environmental Health, Munich, Germany.
Trivedi
A K
AK
Zada
A A Peer
AA
Greif
P A
PA
Mulaw
M A
MA
Christopeit
M
M
Hiddemann
W
W
Bohlander
S K
SK
Behre
G
G
D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D051548:Histone Acetyltransferases / Q000378:metabolism*; D006801:Humans; D000074443:Lysine Acetyltransferase 5; D022423:Myeloid Cells / Q000166:cytology; D011401:Promoter Regions, Genetic; D054730:Protein Interaction Domains and Motifs; D040901:Proteomics / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis
D022763:CCAAT-Enhancer-Binding Protein-alpha; D012333:RNA, Messenger; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5