A novel transcription factor regulates expression of the vacuolar H+-ATPase B2 subunit through AP-2 sites during monocytic differentiation.
During monocyte-to-macrophage differentiation, the cellular content of vacuolar H+-ATPase (V-ATPase) increases more than 4-fold. We have shown previously that amplified expression of the B2 subunit of the V-ATPase occurs solely by increased transcription, and that the 5'-untranslated region of the B2 gene, containing multiple consensus binding sites for the transcription factors AP-2 and Sp1, is required for this expression. The present study demonstrates that AP-2 binding sequences are essential for increased transcription from the B2 promoter during monocyte-macrophage differentiation and that AP-2, expressed exogenously in THP-1 and other cells, activates transcription from the B2 promoter. In mobility shift assays, a nuclear factor from THP-1 and U-937 cells was identified that binds to several AP-2 response elements within the B2 promoter, but does not react with AP-2 antibodies, and has a DNA sequence binding affinity profile that differs from AP-2. These findings suggest that a novel AP-2-like transcription factor is responsible for V-ATPase B subunit amplification during monocyte differentiation.
Lee
B S
BS
Department of Medicine/Renal Division, George M. O'Brien Center for Kidney and Urological Diseases, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Krits
I
I
Crane-Zelkovic
M K
MK
Gluck
S L
SL
D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000502:physiology; D008264:Macrophages / Q000166:cytology; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology* / Q000201:enzymology; D009687:Nuclear Proteins / Q000502:physiology; D011401:Promoter Regions, Genetic; D006180:Proton-Translocating ATPases / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000502:physiology; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000502:physiology*; D025262:Vacuolar Proton-Translocating ATPases
D004268:DNA-Binding Proteins; D007527:Isoenzymes; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D004247:DNA; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases