title: ABCC6 expression is regulated by CCAAT/enhancer-binding protein activating a primate-specific sequence located in the first intron of the gene.
abstract: Pseudoxanthoma elasticum (PXE), a rare recessive genetic disease causing skin, eye, and cardiovascular lesions, is characterized by the calcification of elastic fibers. The disorder is due to loss-of-function mutations of the ABCC6 gene, but the pathophysiology of the disease is still not understood. Here we investigated the transcriptional regulation of the gene, using DNase I hypersensitivity assay followed by luciferase reporter gene assay. We identified three DNase I hypersensitive sites (HSs) specific to cell lines expressing ABCC6. These HSs are located in the proximal promoter and in the first intron of the gene. We further characterized the role of the HSs by luciferase assay and demonstrated the transcriptional activity of the intronic HS. We identified the CCAAT/enhancer-binding protein β (C/EBPβ) as a factor binding the second intronic HS by chromatin immunoprecipitation and corroborated this finding by luciferase assays. We also showed that C/EBPβ interacts with the proximal promoter of the gene. We propose that C/EBPβ forms a complex with other regulatory proteins including the previously identified regulatory factor hepatocyte nuclear factor 4α (HNF4α). This complex would account for the tissue-specific expression of the gene and might serve as a metabolic sensor. Our results point toward a better understanding of the physiological role of ABCC6.
authors: Laboratory of Transcriptional Regulation, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland.
authors: Marcin
authors: M
authors: Ratajewski
authors: Hugues
authors: H
authors: de Boussac
authors: Iwona
authors: I
authors: Sachrajda
authors: Caroline
authors: C
authors: Bacquet
authors: Tünde
authors: T
authors: Kovács
authors: András
authors: A
authors: Váradi
authors: Lukasz
authors: L
authors: Pulaski
authors: Tamás
authors: T
authors: Arányi
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells; D003850:Deoxyribonuclease I / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D057809:HEK293 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007438:Introns / Q000235:genetics; D008156:Luciferases / Q000235:genetics; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D009928:Organ Specificity; D011323:Primates; D011401:Promoter Regions, Genetic / Q000235:genetics; D011561:Pseudoxanthoma Elasticum / Q000235:genetics*
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D003850:Deoxyribonuclease I; D051557:Hepatocyte Nuclear Factor 4; D008156:Luciferases; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C102029:ABCC6 protein, human; C496592:HNF4A protein, human