THE HUMAN A-MYB PROTEIN IS A STRONG ACTIVATOR OF TRANSCRIPTION

Citation
J. Golay et al., THE HUMAN A-MYB PROTEIN IS A STRONG ACTIVATOR OF TRANSCRIPTION, Oncogene, 9(9), 1994, pp. 2469-2479
Citations number
64
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Genetics & Heredity",Oncology
Journal title
ISSN journal
0950-9232
Volume
9
Issue
9
Year of publication
1994
Pages
2469 - 2479
Database
ISI
SICI code
0950-9232(1994)9:9<2469:THAPIA>2.0.ZU;2-6
Abstract
The A-myb gene belongs to the family of the c-myb proto-oncogene. We r eport here the cloning from a B lymphocyte cDNA library of the previou sly missing 3' half of the human A-myb cDNA, thus closing the previous ly still incomplete open reading frame. Analysis of the homologies bet ween the different myb proteins reveals four domains of high conservat ion. We show, using a polyclonal rabbit antibody, that the 90 kd human A-myb protein is nuclear and that it activates transcription from the KHK-CAT reporter 6-10 times more strongly than c-myb in NIH3T3 cells. The transactivating function of A-myb depends on the presence of the myb binding site in the reporter, and on both the DNA binding and acid ic domains of the A-myb protein. The bacterially expressed protein pro tects the myb binding sites of the reporter in footprint experiments. Binding of the A-myb protein is shown in gel retardation assays to be specific for the classical c-myb recognition sequence PyAAC(G)/(T)G. I n addition, like c-myb, A-myb binds more strongly to the MIM-A synthet ic oligonucleotide that carries the TAACGG sequence than to the MBS-I oligonucleotide containing TAAGTG. Finally, DNA binding activity is de monstrated to require the N-terminal portion of the protein containing the three tandem repeats of amino acids conserved in all myb proteins . We have thus shown that the A-myb protein is a strong activator of t ranscription and that this activity depends on both the DNA-binding an d acidic domains.