title: Liganded retinoic acid X receptor α represses connexin 43 through a potential retinoic acid response element in the promoter region.
abstract: Retinoic acid X receptor alpha (RXRα) and Connexin 43 (Cx43) both play a crucial role in cardiogenesis. However, little is known about the interplay mechanism between the RXRα and Cx43.
  
  
  
  The activations of retinoic acid response element (RARE) in Cx43 were measured by luciferase transfection assay. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) was performed to prove that RXRα can directly bind to the RARE sequence. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to analyze the RXRα and Cx43 mRNA level and protein level in cells.
  
  
  
  In this study, we confirmed the negative association of the gene expression between the RXRα and Cx43 in the cell level. Interestingly, a functional RARE was detected in the region from -1,426 to -314 base pairs upstream from the transcriptional start site of Cx43. Moreover, we also prove that RXRα can directly bind to this RARE sequence in vitro and in vivo.
  
  
  
  RXRα negatively regulates the transcription and expression by directly binding to the RARE in the promoter of Cx43. The RARE-like sequence harbored in the Cx43 promoter region may serve as a functional RARE in the retinoic acid (RA) signaling pathway.
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.
authors.forename: Ruoyi
authors.initials: R
authors.lastname: Gu
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.|Present address: Department of Pediatrics, Chengdu Women and Children's Medical Center, Sichuan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.|Shanghai Key Laboratory of Birth Defects, Shanghai, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Wang
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.|Shanghai Key Laboratory of Birth Defects, Shanghai, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sheng
authors.affiliation: Shanghai Key Laboratory of Birth Defects, Shanghai, China.|Key Laboratory of Molecular Medicine, Ministry of Education, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Duan
authors.initials: D
authors.lastname: Ma
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.|Shanghai Key Laboratory of Birth Defects, Shanghai, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Ma
authors.affiliation: Children's Hospital of Fudan University, Shanghai, China.|Shanghai Key Laboratory of Birth Defects, Shanghai, China.
authors.forename: Guoying
authors.initials: G
authors.lastname: Huang
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006321:Heart / Q000196:embryology / Q000254:growth & development; D006801:Humans; D008856:Microscopy, Fluorescence; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D060888:Real-Time Polymerase Chain Reaction; D020218:Response Elements; D000072482:Retinoic Acid Receptor alpha / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D018031:Connexin 43; D000072482:Retinoic Acid Receptor alpha