The DNA binding domain of GR_like nuclear receptors is composed of two C4-type zinc fingers
The DNA binding domain of GR_like nuclear receptors is composed of two C4-type zinc fingers. Each zinc finger contains a group of four Cys residues which co-ordinates a single zinc atom. It interacts with specific DNA sites upstream of the target gene and modulates the rate of transcriptional initiation. This family of NRs includes four types of nuclear hormone receptors: glucocorticoid receptor (GR), mineralocorticoid receptor (MR), progesterone receptor (PR), and androgen receptor (AR). The receptors bind to common DNA elements containing a partial palindrome of the core sequence 5'-TGTTCT-3' with a 3bp spacer. These four receptors regulate some of the most fundamental physiological functions such as the stress response, metabolism, electrolyte homeostasis, immune function, growth, development, and reproduction. The NRs in this family have high sequence homology and share similar functional mechanisms. The dominant mechanism of function is by direct DNA binding and transcriptional regulation of target genes . The GR, MR, PR, and AR exhibit same modular structure. They have a central highly conserved DNA binding domain (DBD), a non-conserved N-terminal domain, a flexible hinge and a C-terminal ligand binding domain (LBD).