Roles of PU.1 in monocyte- and mast cell-specific gene regulation: PU.1 transactivates CIITA pIV in cooperation with IFN-gamma.
Over-expression of PU.1, a myeloid- and lymphoid-specific transcription factor belonging to the Ets family, induces monocyte-specific gene expression in mast cells. However, the effects of PU.1 on each target gene and the involvement of cytokine signaling in PU.1-mediated gene expression are largely unknown. In the present study, PU.1 was over-expressed in two different types of bone marrow-derived cultured mast cells (BMMCs): BMMCs cultured with IL-3 plus stem cell factor (SCF) and BMMCs cultured with pokeweed mitogen-stimulated spleen-conditioned medium (PWM-SCM). PU.1 over-expression induced expression of MHC class II, CD11b, CD11c and F4/80 on PWM-SCM-cultured BMMCs, whereas IL-3/SCF-cultured BMMCs expressed CD11b and F4/80, but not MHC class II or CD11c. When IFN-gamma was added to the IL-3/SCF-based medium, PU.1 transfectant acquired MHC class II expression, which was abolished by antibody neutralization or in Ifngr(-/-) BMMCs, through the induction of expression of the MHC class II transactivator, CIITA. Real-time PCR detected CIITA mRNA driven by the fourth promoter, pIV, and chromatin immunoprecipitation indicated direct binding of PU.1 to pIV in PU.1-over-expressing BMMCs. PU.1-over-expressing cells showed a marked increase in IL-6 production in response to LPS stimulation in both IL-3/SCF and PWM-SCM cultures. These results suggest that PU.1 overproduction alone is sufficient for both expression of CD11b and F4/80 and for amplification of LPS-induced IL-6 production. However, IFN-gamma stimulation is essential for PU.1-mediated transactivation of CIITA pIV. Reduced expression of mast cell-related molecules and transcription factors GATA-1/2 and up-regulation of C/EBPalpha in PU.1 transfectants indicate that enforced PU.1 suppresses mast cell-specific gene expression through these transcription factors.
Ito
Tomonobu
T
Atopy (Allergy) Research Center, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
Nishiyama
Chiharu
C
Nakano
Nobuhiro
N
Nishiyama
Makoto
M
Usui
Yoshihiko
Y
Takeda
Kazuyoshi
K
Kanada
Shunsuke
S
Fukuyama
Kanako
K
Akiba
Hisaya
H
Tokura
Tomoko
T
Hara
Mutsuko
M
Tsuboi
Ryoji
R
Ogawa
Hideoki
H
Okumura
Ko
K
D000818:Animals; D000943:Antigens, Differentiation / Q000276:immunology / Q000378:metabolism; D039481:CD11b Antigen / Q000276:immunology / Q000378:metabolism; D039521:CD11c Antigen / Q000276:immunology / Q000378:metabolism; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005802:Genes, MHC Class II; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology* / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D009000:Monocytes / Q000187:drug effects / Q000276:immunology*; D009687:Nuclear Proteins / Q000235:genetics; D011506:Proteins / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D017471:Receptors, Interferon / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D051941:fms-Like Tyrosine Kinase 3 / Q000494:pharmacology; D000096743:Interferon gamma Receptor; D000099232:Proto-Oncogene Protein Spi-1
D000943:Antigens, Differentiation; D039481:CD11b Antigen; D039521:CD11c Antigen; D017077:Culture Media, Conditioned; D007371:Interferon-gamma; D007377:Interleukin-3; D015847:Interleukin-4; D015850:Interleukin-6; D008070:Lipopolysaccharides; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D017471:Receptors, Interferon; D019089:Stem Cell Factor; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; D051941:fms-Like Tyrosine Kinase 3; D000096743:Interferon gamma Receptor; D000099232:Proto-Oncogene Protein Spi-1; C083728:MHC class II transactivator protein; C036763:monocyte-macrophage differentiation antigen; C034911:serum cancer-suppressive peptide, mouse; C497971:Flt3 protein, mouse