Down regulation of myeloperoxidase gene associated with specific nuclease hypersensitive sites during TPA induced differentiation of HL-60.
The level of myeloperoxidase (MPO) mRNA is reduced significantly after HL-60 induced differentiation with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). We examined the chromatin structural changes of the MPO gene during TPA induction. Before TPA induction about nine DNase I hypersensitive sites (HS) were found on the 5' upstream and at various intron regions of the MPO gene. A new HS was found on intron 8 within 4 h of induction; its appearance preceded down regulation of the MPO gene. At the same time DNase I HS found in 0.3 and 1-1.5 kb upstream of the MPO CAP site, were significantly reduced or disappeared after TPA induction. These chromatin structural changes could be closely linked to the mechanism which regulates the MPO gene expression.
Chang
K S
KS
University of Texas MD Anderson Cancer Center, Division of Laboratory Medicine, Houston 77030.
Zhao
S R
SR
Wang
Y P
YP
Lu
J F
JF
Trujillo
J M
JM
Stass
S A
SA
Freireich
E J
EJ
D015139:Blotting, Southern; D002454:Cell Differentiation / Q000187:drug effects; D003850:Deoxyribonuclease I / Q000378:metabolism*; D015536:Down-Regulation / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000502:physiology; D007942:Leukemia, Experimental / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D007951:Leukemia, Myeloid / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D009195:Peroxidase / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D009195:Peroxidase; D003850:Deoxyribonuclease I; D013755:Tetradecanoylphorbol Acetate