title: C/EBPε participates in all-trans retinoic acid induction of PI3Kγ in U937 cells via an intronic matrix attachment region sequence.
abstract: ATRA (all-trans retinoic acid) regulates gene expression by binding as a ligand to its specific receptors like C/EBPε which is directly induced. In the U937 cell line, PI3Kγ is selectively induced over other PI3Ks by ATRA, although the mechanism is still unclear. Here, we show that C/EBPε and PI3Kγ are induced in U937 cells by ATRA both in levels of mRNA and protein. Reporter gene assay revealed that C/EBPε is able to interact with a previously identified 2 kb MAR (matrix attachment region) sequence in the last intron of PI3Kγ gene, and increases its linked heterogeneous reporter gene expression. ChIP assay showed that induction of endogenous PI3Kγ is at least partially caused by enhanced, direct C/EBPε binding to a 15 bp sequence at nucleotides 1428-1442 within this MAR sequence, and EMSA analysis confirmed this binding in vitro. The results above collectively show that C/EBPε participates in ATRA induction of PI3Kγ.
authors.affiliation: Department of Molecular and Cellular Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, 280# Chongqing Road(S), Shanghai, 200025, People's Republic of China.
authors.forename: Rong
authors.initials: R
authors.lastname: Cai
authors.forename: Xia
authors.initials: X
authors.lastname: Cai
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Weirong
authors.initials: W
authors.lastname: Xu
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
mesh_terms: D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000096:biosynthesis* / Q000235:genetics*; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D007438:Introns / Q000235:genetics*; D008156:Luciferases / Q000378:metabolism; D045170:Matrix Attachment Regions / Q000235:genetics*; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*; D020298:U937 Cells
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; C070790:CEBPE protein, human; D014212:Tretinoin; D008156:Luciferases; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546760:PIK3CG protein, human