Nuclear translocation of beta-actin is involved in transcriptional regulation during macrophage differentiation of HL-60 cells.
Studies have shown that nuclear translocation of actin occurs under certain conditions of cellular stress; however, the functional significance of actin import remains unclear. Here, we demonstrate that during the phorbol 12-myristate 13-acetate (PMA)-induced differentiation of HL-60 cells toward macrophages, beta-actin translocates from the cytoplasm to the nucleus and that this process is dramatically inhibited by pretreatment with p38 mitogen-activated protein kinase inhibitors. Using chromatin immunoprecipitation-on-chip assays, the genome-wide maps of beta-actin binding to gene promoters in response to PMA treatment is analyzed in HL-60 cells. A gene ontology-based analysis shows that the identified genes belong to a broad spectrum of functional categories such as cell growth and differentiation, signal transduction, response to external stimulus, ion channel activity, and immune response. We also demonstrate a correlation between beta-actin occupancy and the recruitment of RNA polymerase II at six selected target genes, and beta-actin knockdown decreases the mRNA expression levels of these target genes induced by PMA. We further show that nuclear beta-actin is required for PMA-induced transactivation of one target gene, solute carrier family 11 member 1, which is important for macrophage activation. Our data provide novel evidence that nuclear accumulation of beta-actin is involved in transcriptional regulation during macrophage-like differentiation of HL-60 cells.
Xu
Yong Zhong
YZ
Department of Medicine and Human Genetics and Department of Biology, Bioinformatics Centre, McGill University, McGill University Health Centre, Montreal General Hospital Research Institute, Montreal, QC, Canada.
Thuraisingam
Thusanth
T
Morais
David Anderson de Lima
DA
Rola-Pleszczynski
Marek
M
Radzioch
Danuta
D
D000199:Actins / Q000378:metabolism*; D021581:Active Transport, Cell Nucleus; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D018922:HL-60 Cells; D006801:Humans; D017403:In Situ Hybridization; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D000199:Actins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D013755:Tetradecanoylphorbol Acetate