3D Structure Determination of a Human Prostate-Specific Homeoprotein, NKX3.1: The Mechanism of Autoregulation Through its Terminal Domains

摘要

NKX3.l, a member of the NK class of homeodomain (HD) proteins, is expressed primarily in the adult prostate and has growth suppression and differentiating effects in prostate epithelial cells. NKX3.l consists of three domains having the HD in the middle. The NKX3.l HD is known to binds to DNA for its transcriptional activity and other transcriptional factors such as serum response factor (SRF). Our goal is to determine 3D structure of NKX3.l to elucidate the mechanism of its functions and regulations. During the first year, full-length as well as various truncation constructs of NKX3.l, including N- terminal deletions, C-terminal deletions, and HD only, were made and purified in a sufficient quantity for the structural characterization by NMR and circular dichroism (CD). The interaction between NKX3.l HD and DNA was confirmed by EMSA and NNR, and the binding of SRF to NKX3.l HD was confirmed by NMR. Using the L3C/l5N double labeled NKX3.l HD in complex with DNA, a suite of 3D NMR experiments were recorded for the backbone and sidechain resonance assignments. The spectral analysis is in progress and soon we will be able to calculate 3D NNR structures of the complex. We will continue our structural study with full- length NKX3.l.