Nucleolin is involved in interferon regulatory factor-2-dependent transcriptional activation.
We have previously shown that interferon regulatory factor-2 (IRF-2) is acetylated in a cell growth-dependent manner, which enables it to contribute to the transcription of cell growth-regulated promoters. To clarify the function of acetylation of IRF-2, we investigated the proteins that associate with acetylated IRF-2. In 293T cells, the transfection of p300/CBP-associated factor (PCAF) enhanced the acetylation of IRF-2. In cells transfected with both IRF-2 and PCAF, IRF-2 associated with endogenous nucleolin, while in contrast, minimal association was observed when IRF-2 was transfected with a PCAF histone acetyl transferase (HAT) deletion mutant. In a pull-down experiment using stable transfectants, acetylation-defective mutant IRF-2 (IRF-2K75R) recruited nucleolin to a much lesser extent than wild-type IRF-2, suggesting that nucleolin preferentially associates with acetylated IRF-2. Nucleolin in the presence of PCAF enhanced IRF-2-dependent H4 promoter activity in NIH3T3 cells. Nucleolin knock-down using siRNA reduced the IRF-2/PCAF-mediated promoter activity. Chromatin immunoprecipitation analysis indicated that PCAF transfection increased nucleolin binding to IRF-2 bound to the H4 promoter. We conclude that nucleolin is recruited to acetylated IRF-2, thereby contributing to gene regulation crucial for the control of cell growth.
Masumi
A
A
Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo, Japan. amasumi@nih.go.jp
Fukazawa
H
H
Shimazu
T
T
Yoshida
M
M
Ozato
K
K
Komuro
K
K
Yamaguchi
K
K
D016475:3T3 Cells; D000107:Acetylation; D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D017353:Gene Deletion; D051548:Histone Acetyltransferases / Q000235:genetics; D006801:Humans; D050836:Interferon Regulatory Factor-2 / Q000235:genetics / Q000502:physiology*; D051379:Mice; D009154:Mutation; D010750:Phosphoproteins / Q000502:physiology*; D011401:Promoter Regions, Genetic; D016601:RNA-Binding Proteins / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000502:physiology*; D000097796:Nucleolin
D051548:Histone Acetyltransferases; D050836:Interferon Regulatory Factor-2; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D050880:p300-CBP Transcription Factors; D000097796:Nucleolin; C494229:IRF2 protein, human