The DNA-binding domain of human c-Abl tyrosine kinase promotes the interaction of a HMG chromosomal protein with DNA

• Published in: Nucleic acids research Vol. 27; no. 11; pp. 2265 - 2270
• Main Authors: David-Cordonnier, Marie-Hélène, Payet, Dominique, D'Halluin, Jean-Claude, Waring, Michael J., Travers, Andrew A., Bailly, Christian
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.06.1999; Oxford Publishing Limited (England)
• Subjects: Animals; Base Pairing; Binding Sites; Binding, Competitive; DNA, Circular - metabolism; DNA-Binding Proteins - metabolism; Drosophila melanogaster; High Mobility Group Proteins - metabolism; Humans; Insect Proteins - metabolism; Proto-Oncogene Proteins c-abl - metabolism; Spectrophotometry - methods; Substrate Specificity
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/27.11.2265

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.