cAMP-dependent protein kinase is necessary for increased NF-E2.DNA complex formation during erythroleukemia cell differentiation.
When murine erythroleukemia (MEL) cells are induced to differentiate by hexamethylene bisacetamide (HMBA), erythroid-specific genes are transcriptionally activated; however, transcriptional activation of these genes is severely impaired in cAMP-dependent protein kinase (protein kinase A)-deficient MEL cells. The transcription factor NF-E2, composed of a 45-kDa (p45) and an 18-kDa (p18) subunit, is essential for enhancer activity of the globin locus control regions (LCRs). DNA binding of NF-E2 and alpha-globin LCR enhancer activity was significantly less in HMBA-treated protein kinase A-deficient cells compared to cells containing normal protein kinase A activity; DNA binding of several other transcription factors was the same in both cell types. In parental cells, HMBA treatment and/or prolonged activation of protein kinase A increased the amount of NF-E2.DNA complexes without change in DNA binding affinity; the expression of p45 and p18 was the same under all conditions. p45 and p18 were phosphorylated by protein kinase A in vitro, but the phosphorylation did not affect NF-E2.DNA complexes, suggesting that protein kinase A regulates NF-E2.DNA complex formation indirectly, e.g. by altering expression of a regulatory factor(s). Thus, protein kinase A appears to be necessary for increased NF-E2.DNA complex formation during differentiation of MEL cells and may influence erythroid-specific gene expression through this mechanism.
Garingo
A D
AD
Department of Medicine, University of California at San Diego, La Jolla 92093-0652, USA.
Suhasini
M
M
Andrews
N C
NC
Pilz
R B
RB
D001483:Base Sequence; D002454:Cell Differentiation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology*; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D050981:Erythroid-Specific DNA-Binding Factors; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism / Q000473:pathology*; D008969:Molecular Sequence Data; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; D014157:Transcription Factors; D004247:DNA; D017868:Cyclic AMP-Dependent Protein Kinases