title: Sequence-specific deoxyribonucleic acid (DNA) recognition by steroidogenic factor 1: a helix at the carboxy terminus of the DNA binding domain is necessary for complex stability.
abstract: Steroidogenic factor 1 (SF1) is a member of the NR5A subfamily of nuclear hormone receptors and is considered a master regulator of reproduction because it regulates a number of genes encoding reproductive hormones and enzymes involved in steroid hormone biosynthesis. Like other NR5A members, SF1 harbors a highly conserved approximately 30-residue segment called the FTZ-F1 box C-terminal to the core DNA binding domain (DBD) common to all nuclear receptors and binds to 9-bp DNA sequences as a monomer. Here we describe the solution structure of the SF1 DBD in complex with an atypical sequence in the proximal promoter region of the inhibin-alpha gene that encodes a subunit of a reproductive hormone. SF1 forms a specific complex with the DNA through a bipartite motif binding to the major and minor grooves through the core DBD and the N-terminal segment of the FTZ-F1 box, respectively, in a manner previously described for two other monomeric receptors, nerve growth factor-induced-B and estrogen-related receptor 2. However, unlike these receptors, SF1 harbors a helix in the C-terminal segment of the FTZ-F1 box that interacts with both the core DBD and DNA and serves as an important determinant of stability of the complex. We propose that the FTZ-F1 helix along with the core DBD serves as a platform for interactions with coactivators and other DNA-bound factors in the vicinity.
authors.affiliation: Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA.
authors.forename: Tanya H
authors.initials: TH
authors.lastname: Little
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Christina K
authors.initials: CK
authors.lastname: Matulis
authors.forename: Jennifer
authors.initials: J
authors.lastname: Weck
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Aparna
authors.initials: A
authors.lastname: Ramachandran
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Mayo
authors.forename: Ishwar
authors.initials: I
authors.lastname: Radhakrishnan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006860:Hydrogen Bonding; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; D046911:Macromolecular Substances; C515057:NR5A1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse; D004247:DNA