Transcriptional regulation of human G2A in monocytes/ macrophages: involvement of c/EBPs, Runx and Pu.1.
G2 accumulation (G2A) is a G-protein coupled receptor, activated by several ligands and stimuli, such as lysophosphatidylcholine (LPC), extracellular low pH and oxidized phospholipids including 9- and 13-hydroxyoctadecadienoic acid, and has been implicated in mediating inflammatory process under oxidative conditions. Recently, it was demonstrated that G2A in monocytes/macrophages plays critical roles in atherosclerosis deterioration, and therefore its transcriptional regulation in monocytes/macrophages is of great interest. Here, we first confirmed the expression of human G2A (hG2A) in lymph nodes, spleen and peripheral blood leukocytes, including monocytes. Thereafter, transcription start site (TSS) of hG2A was determined by 5'-rapid amplification of cDNA ends analysis. In the course of the analysis, we found that two transcriptional variants, hG2A-a and -b, are produced by alternative splicing, resulting in the production of N-terminal different hG2A proteins with similar sensitivity to low pH and LPC. Using a monocytic cell line THP-1 as a model, transcription of hG2A was precisely examined, and we demonstrated that it is dependent both on the chromatin structure around TSS, and on the binding of the transcription factors (c/EBPalpha and beta, Runx1 and Pu.1) to their cis-elements, located at the core promoter just upstream of TSS.
Murakami
Naoka
N
Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Hashidate
Tomomi
T
Harayama
Takeshi
T
Yokomizo
Takehiko
T
Shimizu
Takao
T
Nakamura
Motonao
M
D015152:Blotting, Northern; D015139:Blotting, Southern; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D000099232:Proto-Oncogene Protein Spi-1
D022782:CCAAT-Enhancer-Binding Protein-beta; D018797:Cell Cycle Proteins; D050676:Core Binding Factor Alpha 2 Subunit; D008244:Lysophosphatidylcholines; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C115270:G2A receptor; C493728:RUNX1 protein, human