A naturally occurring steroidogenic factor-1 mutation exhibits differential binding and activation of target genes.
Steroidogenic factor-1 (SF-1) is an orphan nuclear receptor that binds DNA as a monomer and regulates the transcription of multiple target genes. A mutation in the proximal (P)-box of the first zinc finger of SF-1 (G35E) has been reported to cause complete XY sex reversal and adrenal insufficiency. Because this P-box region dictates DNA binding specificity, we investigated the effect of this mutation on DNA binding and regulation of target genes. Binding of the P-box mutant was markedly impaired for most native SF-1 response elements. However, mutant SF-1 bound to a subset of response elements containing a CCA AGGTCA motif. Mutagenesis studies of response elements revealed that the first nucleotide position in the 5'-flanking sequence triplet and the central part of the half-site dictate DNA binding specificity by the mutant SF-1. Further, introduction of a mutation into the SF-1 A-box, which has been proposed to bind to the 5'-flanking sequence triplet, eliminated binding by mutant SF-1 to all response elements tested. These data support the idea that the A-box stabilizes monomeric binding by nuclear receptors. This action may be particularly important when P-box binding affinity is compromised either by mutations in SF-1 or by sequence alterations in its binding site.
Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
M
M
Ito
J C
JC
Achermann
J L
JL
Jameson
D000595:Amino Acid Sequence; D000818:Animals; D001141:Aromatase / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D020218:Response Elements / Q000235:genetics*; D054339:Steroidogenic Factor 1; D013379:Substrate Specificity; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics*; D016335:Zinc Fingers / Q000235:genetics*
D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C515057:NR5A1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515058:steroidogenic factor 1, mouse; C515060:steroidogenic factor 1, rat; D004247:DNA; D001141:Aromatase