title: Induction of disabled-2 gene during megakaryocyte differentiation of k562 cells.
abstract: Megakaryocyte differentiation is often accompanied by the changes of gene expression pattern. Here we reported that the expression of DAB2, a putative adaptor protein in cell signaling, was induced at the protein and mRNA levels upon 12-O-tetradecanoylphorbol-13-acetate-mediated megakaryocyte differentiation of human chronic myeloid leukemic K562 cells. On the other hand, the differentiation agents DMSO and retinoic acid had no effect on DAB2 expression. Analysis of promoter activity with the human DAB2 luciferase reporter constructs suggested that the regulation is partially at the transcriptional level. The responsive sequences located within an 80-bp DAB2 promoter region. To determine the involvement of MEK1-p42/p44 MAPK pathway in mediating DAB2 gene expression, we have performed the following experiments and found that (i) there was sustained activation of p42/p44 MAPK, but not p38 MAPK, upon K562 cells differentiation; (ii) application of MEK1 inhibitor U0126 reduced the expression of DAB2 protein, mRNA and promoter activity, as well as cell differentiation; (iii) constitutively active MEK1 increased DAB2 promoter activity; and (iv) dominant negative ERK2 abolished constitutively active MEK1-induced DAB2 promoter activity. Taken together, our results indicate that DAB2 gene is induced upon megakaryocyte differentiation by the MEK1-p42/p44 MAPK pathway and may define a new role of DAB2 in hematopoietic cell differentiation.
authors: School of Medical Technology, Chang Gung University, Tao-Yuan, Taiwan, Republic of China. ctseng@mail.cgu.edu.tw
authors: C P
authors: CP
authors: Tseng
authors: C H
authors: CH
authors: Huang
authors: C C
authors: CC
authors: Tseng
authors: M H
authors: MH
authors: Lin
authors: J T
authors: JT
authors: Hsieh
authors: C H
authors: CH
authors: Tseng
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics*; D004247:DNA; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D020014:K562 Cells; D008533:Megakaryocytes / Q000166:cytology*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D025521:Tumor Suppressor Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; C102885:DAB2 protein, human; D011506:Proteins; D025521:Tumor Suppressor Proteins; D004247:DNA; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate