Document Detail

Truncated c-Myb expression in the human leukemia cell line TK-6.
MedLine Citation:
PMID:  9737692     Owner:  NLM     Status:  MEDLINE    
The c-MYB proto-oncogene encodes a transcription factor which plays an important role in hematopoiesis. We detected truncated c-MYB mRNA (2.0 kb) and c-Myb protein (55 kDa) in the TK-6 cell line, which was established from a patient with chronic myelogenous leukemia in T cell blast crisis. Mutated c-MYB cDNA clone (WTK-1) was isolated from a TK-6 cell cDNA library and sequenced in its entirety. Compared with the wild-type human c-MYB sequence, the WTK-1 sequence diverged at the 3' ends of exons 9. A termination codon was present as the second codon downstream from the point of divergence and was followed by a previously unknown rearranged sequence. The conceptual protein encoded by WTK-1 (Myb(TK-6)) comprises 402 amino acids and lacks the negative regulatory domain of the normal c-Myb, reminiscent of the activated form of Myb protein. Luciferase reporter assay in NIH3T3 cells showed that the expression vector encoding Myb(TK-6) stimulated Myb-regulated mim-1 promoter more effectively than that encoding wild-type human c-Myb, suggesting that Myb(TK-6) is functional as a transcription factor, and thus as a potential transforming protein. Southern blot and mutant allele-specific polymerase chain reaction analyses showed that the same rearrangement of the c-MYB gene in TK-6 was present in late, but not in early, specimens obtained from the patient, indicating that this mutation had been acquired during disease progression.
A Tomita; T Watanabe; H Kosugi; H Ohashi; T Uchida; T Kinoshita; S Mizutani; T Hotta; T Murate; M Seto; H Saito
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Leukemia     Volume:  12     ISSN:  0887-6924     ISO Abbreviation:  Leukemia     Publication Date:  1998 Sep 
Date Detail:
Created Date:  1998-09-24     Completed Date:  1998-09-24     Revised Date:  2013-03-04    
Medline Journal Info:
Nlm Unique ID:  8704895     Medline TA:  Leukemia     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1422-9     Citation Subset:  IM    
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
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MeSH Terms
Base Sequence
Blast Crisis / metabolism
Chromosomes, Human, Pair 6 / genetics*
DNA, Complementary / genetics
DNA, Neoplasm / genetics
HL-60 Cells
HeLa Cells
Leukemia, Myelogenous, Chronic, BCR-ABL Positive / metabolism*
Molecular Sequence Data
Proto-Oncogene Proteins / genetics*,  metabolism
Proto-Oncogene Proteins c-myb
Sequence Analysis, DNA
Trans-Activators / genetics*,  metabolism
Transcriptional Activation
Tumor Cells, Cultured
Reg. No./Substance:
0/DNA, Complementary; 0/DNA, Neoplasm; 0/Proto-Oncogene Proteins; 0/Proto-Oncogene Proteins c-myb; 0/Trans-Activators

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