Nucleic Acids Research, Vol 27, Issue 11 2265-2270, Copyright © 1999 by Oxford University Press
MH David-Cordonnier, D Payet, JC D'Halluin, MJ Waring, AA Travers and C Bailly
The biological activity of the c-Abl protein is linked to its tyrosine
kinase and DNA-binding activities. The protein, which plays a major role in
the cell cycle response to DNA damage, interacts preferentially with
sequences containing an AAC motif and exhibits a higher affinity for bent
or bendable DNA, as is the case with high mobility group (HMG) proteins. We
have compared the DNA-binding characteristics of the DNA- binding domain of
human c-Abl and the HMG-D protein from Drosophila melanogaster. c-Abl binds
tightly to circular DNA molecules and potentiates the interaction of DNA
with HMG-D. In addition, we used a series of DNA molecules containing
modified bases to determine how the exocyclic groups of DNA influence the
binding of the two proteins. Interfering with the 2-amino group of purines
affects the binding of the two proteins similarly. Adding a 2-amino group
to adenines restricts the access of the proteins to the minor groove,
whereas deleting this bulky substituent from guanines facilitates the
protein- DNA interaction. In contrast, c-Abl and HMG-D respond very
differently to deletion or addition of the 5-methyl group of pyrimidine
bases in the major groove. Adding a methyl group to cytosines favours the
binding of c-Abl to DNA but inhibits the binding of HMG-D. Conversely,
deleting the methyl group from thymines promotes the interaction of the DNA
with HMG-D but diminishes its interaction with c-Abl. The enhanced binding
of c-Abl to DNA containing 5-methylcytosine residues may result from an
increased propensity of the double helix to denature locally coupled with a
protein-induced reduction in the base stacking interaction. The results
show that c-Abl has unique DNA-binding properties, quite different from
those of HMG-D, and suggest an additional role for the protein kinase.
ARTICLES
The DNA-binding domain of human c-Abl tyrosine kinase promotes the interaction of a HMG chromosomal protein with DNA
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