Characterization of the DNA-binding and dimerization properties of the nuclear orphan receptor germ cell nuclear factor.
The orphan receptor germ cell nuclear factor (GCNF) is a member of the superfamily of nuclear receptors. During development, GCNF exhibits a restricted brain-specific expression pattern, whereas GCNF expression in the adult is germ cell specific. Therefore, the receptor may participate in the regulation of neurogenesis and reproductive functions. No natural GCNF target gene has yet been identified, but recent data demonstrate specific and high-affinity binding of GCNF either to the direct repeat DNA element AGGTCAAGGTCA (DR0) or to extended half-sites, such as TCAAGGTCA. In this study, we show that murine GCNF (mGCNF) can bind as a homodimer to extended half-sites, thus describing a novel property within the nuclear receptor superfamily. Homodimeric binding to extended half-sites requires the presence of a dimerization function within the mGCNF DNA-binding domain (DBD) and a novel dimerization surface encompassing the putative helix 3 and the helix 12 region of the mGCNF ligand-binding domain (LBD). In addition, the mGCNF LBD has the potential to adopt different conformations with distinct dimerization properties. The helix 12 region of the mGCNF LBD not only regulates the switch between these dimerization conformations but also dictates the DNA-binding behavior and transcriptional properties of the different dimerization conformations. In summary, our findings describe unique DNA-binding and dimerization properties of a nuclear receptor and suggest a novel mechanism that allows mGCNF to modulate target gene activity.
Greschik
H
H
Institut für Experimentelle Krebsforschung, Klinik für Tumorbiologie an der Universität Freiburg, D-79106 Freiburg, Germany.
Wurtz
J M
JM
Hublitz
P
P
Köhler
F
F
Moras
D
D
Schüle
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D051838:COUP Transcription Factor I; D002460:Cell Line; D002461:Cell Line, Transformed; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D006801:Humans; D008024:Ligands; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D057136:Nuclear Receptor Subfamily 6, Group A, Member 1; D011487:Protein Conformation; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000737:chemistry; D047488:Retinoid X Receptors; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry; D014158:Transcription, Genetic
D051838:COUP Transcription Factor I; D004268:DNA-Binding Proteins; D008024:Ligands; C497589:NR2F1 protein, human; C539950:NR6A1 protein, human; C497590:Nr2f1 protein, mouse; C539954:Nr6a1 protein, mouse; D057136:Nuclear Receptor Subfamily 6, Group A, Member 1; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D004247:DNA