The hematopoietic cell-specific transcription factor PU.1 is critical for expression of CD11c.
PU.1 is a hematopoietic cell-specific transcription factor belonging to the Ets family, which plays an important role in the development of dendritic cells (DCs). CD11c (encoded by Itgax) is well established as a characteristic marker of hematopoietic lineages including DCs. In the present study, we analyzed the role of PU.1 (encoded by Spi-1) in the expression of CD11c. When small interfering RNA (siRNA) for Spi-1 was introduced into bone marrow-derived DCs (BMDCs), the mRNA level and cell surface expression of CD11c were dramatically reduced. Using reporter assays, the TTCC sequence at -56/-53 was identified to be critical for PU.1-mediated activation of the promoter. An EMSA showed that PU.1 directly bound to this region. ChIP assays demonstrated that a significant amount of PU.1 bound to this region on chromosomal DNA in BMDCs, which was decreased in LPS-stimulated BMDCs in accordance with the reduced levels of mRNAs of Itgax and Spi-1, and the histone acetylation degree. Enforced expression of exogenous PU.1 induced the expression of the CD11c protein on the cell surface of mast cells, whereas control transfectants rarely expressed CD11c. Quantitative RT-PCR also showed that the expression of a transcription factor Irf4, which is a partner molecule of PU.1, was reduced in PU.1-knocked down BMDCs. IRF4 transactivated the Itgax gene in a synergistic manner with PU.1. Taken together, these results indicate that PU.1 functions as a positive regulator of CD11c gene expression by directly binding to the Itgax promoter and through transactivation of the Irf4 gene.
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.|Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Takuya
T
Yashiro
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.|Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Kazumi
K
Kasakura
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
Yoshihito
Y
Oda
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Nao
N
Kitamura
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
Akihito
A
Inoue
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
Shusuke
S
Nakamura
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.|Laboratory of Cell Biotechnology, Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Hokuto
H
Yokoyama
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.|Laboratory of Cell Biotechnology, Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Kanako
K
Fukuyama
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Mutsuko
M
Hara
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Hideoki
H
Ogawa
Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Ko
K
Okumura
Laboratory of Cell Biotechnology, Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Makoto
M
Nishiyama
Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.|Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Chiharu
C
Nishiyama
D000107:Acetylation; D000818:Animals; D039521:CD11c Antigen / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics; D003713:Dendritic Cells / Q000502:physiology*; D005786:Gene Expression Regulation; D006410:Hematopoiesis / Q000235:genetics; D006657:Histones / Q000378:metabolism; D050835:Interferon Regulatory Factors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000099232:Proto-Oncogene Protein Spi-1; D000099218:Interferon Regulatory Factor-4
D039521:CD11c Antigen; D004268:DNA-Binding Proteins; D006657:Histones; D050835:Interferon Regulatory Factors; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; D000099218:Interferon Regulatory Factor-4; C423918:Spic protein, mouse
CD11c/Itgax; IRF4/Irf4; PU.1/Spi-1; dendritic cell; transcription factor