Fluctuation of gene expression for poly(ADP-ribose) synthetase during hemin-induced erythroid differentiation of human leukemia K562 cells and its reversion process.
We have studied the regulation of gene expression for poly(ADP-ribose) synthetase during erythroid differentiation and its reversion process. When human leukemia K562 cells were incubated in the presence of 80 microM hemin, benzidine-positive cells appeared at day 2 and 90% of the cells became positive at day 6. However, RNA blot analysis reveals that mRNA for gamma-globin was already abundant in untreated K562 cells and the level of the message was slightly increased by hemin-treatment. Spectroscopic analysis and polyacrylamide gel electrophoresis of the induced cell extracts indicate that hemoglobin molecules were not detected in untreated cells, and increased successively up to day 6. The hemin-induced cells were thoroughly washed, and then recultured in the absence of hemin. The benzidine-positive cells mostly disappeared 3 days after the elimination of the inducer. During the hemin-induced erythroid differentiation, the activity and mRNA for poly(ADP-ribose) synthetase decreased to 50% and 20% of the initial level at day 3 and a low level of the gene expression was maintained afterwards, whereas the activity and mRNA returned to the initial value 1 day after hemin elimination. The results indicate that the hemin-induced erythroid differentiation of K562 cells is a reversible process and depression of the synthetase may be involved in the progress of differentiation.
Tomoda
T
T
Department of Pediatrics, Kochi Medical School, Kochi, Japan.
Kurashige
T
T
Yamamoto
H
H
Fujimoto
S
S
Taniguchi
T
T
D015152:Blotting, Northern; D002454:Cell Differentiation / Q000187:drug effects*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000166:cytology*; D005434:Flow Cytometry; D015971:Gene Expression Regulation, Enzymologic; D006427:Hemin / Q000494:pharmacology*; D006454:Hemoglobins / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D007938:Leukemia / Q000473:pathology*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured
D006454:Hemoglobins; D012333:RNA, Messenger; D006427:Hemin; D011065:Poly(ADP-ribose) Polymerases