Transcription factor egr-1 is involved in phorbol 12-myristate 13-acetate-induced megakaryocytic differentiation of K562 cells.
Transcription factors play important roles in regulating cell growth and differentiation. egr-1, a transcription factor of the zinc finger family, is rapidly activated in many types of cells after mitogen treatment. In this report, we demonstrate that egr-1 mRNA expression, detected by Northern blotting, is activated within 30 min of treatment of the erythroleukemia cell line K562 with phorbol 12-myristate 13-acetate (PMA), and the increased egr-1 mRNA level is associated with an elevated egr-1 antigen expression detected by Western blotting and with its DNA binding activity shown by the gel mobility shift assay. In addition, PMA-mediated activation of egr-1 mRNA expression involves no new protein synthesis and is followed by sequential down-regulation of the mRNA level of GATA-1 and glycophorin A. On the other hand, CD41a surface antigen expression is dramatically up-regulated. Furthermore, enforced expression of egr-1, through transfection of K562 cells with the egr-1 expression plasmid construct, results in expression of the egr-1 transcript that accompanies a significant accumulation on the cell surface of CD41a but not CD14 nor glycophorin A. These observations suggest that egr-1 is involved in regulating PMA-induced megakaryocytic differentiation of K562 cell line.
Cheng
T
T
Hipple Cancer Research Center, Dayton, Ohio 45439-2092.
Wang
Y
Y
Dai
W
W
D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D006801:Humans; D017874:Immediate-Early Proteins; D008533:Megakaryocytes / Q000166:cytology / Q000187:drug effects*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D013755:Tetradecanoylphorbol Acetate