Reciprocal regulation of expression of the human adenosine 5'-triphosphate binding cassette, sub-family A, transporter 2 (ABCA2) promoter by the early growth response-1 (EGR-1) and Sp-family transcription factors.
The human ABCA2 transporter gene encodes a member of a large family of ATP-binding proteins that transport a variety of macromolecules across biological membranes. We have performed luciferase reporter gene assays with promoter constructs comprising the 5'-flanking region to identify cis-regulatory DNA elements and have mapped the minimal promoter region to 321 bp upstream of the translation start site. We have discovered a functional role for two GC-boxes located in the proximal promoter of the ABCA2 gene that contain overlapping sites for the EGR-1 and Sp1 transcription factors. We observed that oligonucleotides containing overlapping EGR-1/Sp1 sites bind the Sp1, Sp3 and Sp4 transcription factors. When BE(2)-M17 cells were treated with phorbol 12-myristate 13-acetate, we observed inducible expression and binding of the EGR-1 transcription factor to the two GC-boxes. Transfection of Sp1, Sp3 or Sp4 expression constructs into Drosophila S2 induced a dose-dependent increase in transcriptional activation of the ABCA2 promoter, but transfection of EGR-1 alone failed to activate transcription. When increasing amounts of EGR-1 were transfected into the BE(2)-M17 neuroblastoma cells we observed a dose-dependent decrease in expression of the ABCA2 promoter, although expression of the endogenous ABCA2 gene increased following transfection of EGR-1.
Davis
Warren
W
Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
Chen
Zhijian J
ZJ
Ile
Kristina E
KE
Tew
Kenneth D
KD
D024506:5' Flanking Region; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000502:physiology*; D004330:Drosophila / Q000378:metabolism; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation; D006801:Humans; D017874:Immediate-Early Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020218:Response Elements; D016329:Sp1 Transcription Factor / Q000502:physiology*; D051705:Sp3 Transcription Factor; D051706:Sp4 Transcription Factor; D014157:Transcription Factors / Q000502:physiology*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
C418186:ABCA2 protein, human; D018528:ATP-Binding Cassette Transporters; D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; C497121:SP3 protein, human; C497124:SP4 protein, human; D016329:Sp1 Transcription Factor; D051706:Sp4 Transcription Factor; D014157:Transcription Factors; D051705:Sp3 Transcription Factor