Role of FOXA and Sp1 in mitochondrial acylcarnitine carrier gene expression in different cell lines.
This study investigates the transcriptional role of the human mitochondrial carnitine/acylcarnitine carrier (CAC) proximal promoter. Through deletion analysis, an activation domain (-334/-80 bp) was identified which contains FOXA and Sp1 active sites. The wild-type (but not mutated) -334/-80 bp region of the CAC gene conferred 74% LUC transgene activity in HepG2 cells, 17% in HEK293 cells and 14% in SK-N-SH cells as compared to that observed with the entire -1503/+3 bp proximal promoter. Overexpression and silencing of FOXA2 or Sp1 in HepG2 cells enhanced and diminished, respectively, LUC activity, CAC transcript and CAC protein. In HEK293 and SK-N-SH cells, which do not contain FOXA1-3, LUC activity was increased by FOXA2 overexpression to a greater extent than in HepG2 cells. Both FOXA2 and Sp1 in HepG2, and only Sp1 in HEK293 and SK-N-SH cells, were found to be bound to the CAC proximal promoter. These results show that FOXA and Sp1 sites in HepG2 cells and only the Sp1 site in HEK293 and SK-N-SH cells have a critical role in the transcriptional regulation of the CAC proximal promoter.
Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy.
Paolo
P
Convertini
Vittoria
V
Infantino
Faustino
F
Bisaccia
Ferdinando
F
Palmieri
Vito
V
Iacobazzi
D001665:Binding Sites / Q000235:genetics; D002331:Carnitine / Q000031:analogs & derivatives / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D057809:HEK293 Cells; D051541:Hepatocyte Nuclear Factor 3-alpha / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics*; D008928:Mitochondria / Q000201:enzymology*; D009154:Mutation; D011401:Promoter Regions, Genetic; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
C496499:FOXA1 protein, human; D051541:Hepatocyte Nuclear Factor 3-alpha; D026901:Membrane Transport Proteins; D016329:Sp1 Transcription Factor; C116917:acylcarnitine; C120109:SLC25A20 protein, human; D002331:Carnitine