Progress Update: Structural studies of DUX4-DNA interaction

by Hideki Aihara PhD
See grant Structural studies of DUX4-DNA interaction

The aims for this research are to both determine the structure of DUX4 homeodomains-DNA complex using x-ray crystallography, and probe the structure and dynamics of free DUX4 and DUX4-homeodomains-DNA complex by NMR spectroscopy.

The 3D structures of Dux4–DNA complexes provide insights into the DNA-binding mechanisms of the unique tandem homeodomains in Dux4. Homeodomains consist of ∼60 amino acids that form a three-helix bundle, of which the third helix is the recognition helix. The latter is inserted into the DNA major groove, which provides a unique signature of the functional groups of the bases and accounts for base readout. The flexible N-terminal tail is inserted into the minor groove that, in turn, accounts for shape readout. Despite the wealth of information available regarding how individual homeodomains interact with DNA, it has been poorly understood how the two homeodomains of Dux4 cooperate in recognizing specific target DNA sequences.

We have solved a high-resolution crystal structure of the human Dux4 homeodomains in complex with DNA to reveal the molecular mechanisms underlying the sequence-specific DNA-binding of Dux4. We are further investigating the structure and dynamics of the Dux4 homeodomains using NMR spectroscopy.

We hope that the atomic details of the Dux4-DNA interactions will facilitate development of specific inhibitors to modulate the Dux4 activity in human cells for treatment of FSH.