Functional analysis of DNA bending and unwinding by the high mobility group domain of LEF-1

AUTOR(ES)

Giese, Klaus

FONTE

The National Academy of Sciences of the USA

RESUMO

LEF-1 (lymphoid enhancer-binding factor 1) is a cell type-specific member of the family of high mobility group (HMG) domain proteins that recognizes a specific nucleotide sequence in the T cell receptor (TCR) α enhancer. In this study, we extend the analysis of the DNA-binding properties of LEF-1 and examine their contributions to the regulation of gene expression. We find that LEF-1, like nonspecific HMG-domain proteins, can interact with irregular DNA structures such as four-way junctions, albeit with lower efficiency than with specific duplex DNA. We also show by a phasing analysis that the LEF-induced DNA bend is directed toward the major groove. In addition, we find that the interaction of LEF-1 with a specific binding site in circular DNA changes the linking number of DNA and unwinds the double helix. Finally, we identified two nucleotides in the LEF-1-binding site that are important for protein-induced DNA bending. Mutations of these nucleotides decrease both the extent of DNA bending and the transactivation of the TCRα enhancer by LEF-1, suggesting a contribution of protein-induced DNA bending to the function of TCRα enhancer.

Documentos Relacionados

• High-mobility-group 1 protein mediates DNA bending as determined by ring closures.
• The Notch Intracellular Domain Can Function as a Coactivator for LEF-1
• Baculovirus Replication Factor LEF-1 Is a DNA Primase†
• Characterization of the interaction between the baculovirus replication factors LEF-1 and LEF-2.
• The role of intercalating residues in chromosomal high-mobility-group protein DNA binding, bending and specificity