title: Role of the LXXLL-motif and activation function 2 domain in subcellular localization of Dax-1 (dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1).
abstract: Dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (Dax-1, NR0B1) is an orphan nuclear receptor that represses transcription by Ad4 binding protein/steroidogenic factor 1 (Ad4BP/SF-1, NR5A1). Observations on human diseases and the phenotypes of mice, in which the corresponding genes have been disrupted, have elucidated essential roles of these two nuclear receptors in differentiation of steroidogenic tissues. However, little is known about how the functions of these factors are regulated. Here we have examined their subcellular localization and have clarified the molecular mechanisms regulating subcellular localization of Dax-1. Prompted by the finding that nuclear localization of Dax-1 correlates with the presence of Ad4BP/SF-1 in the early stages of pituitary development, we have tested the possibility that interaction between the two factors is essential for the nuclear localization of Dax-1. In vitro studies with cultured cells demonstrated that an interaction involving the LXXLL motifs in the N-terminal repeat region of Dax-1 plays a key role in its subcellular localization. In addition, we found that a mutant form of DAX-1 (L466R), from a patient with adrenal hypoplasia congenita, was defective in nuclear localization in spite of having an intact N terminus. Taken together, the results reveal that the subcellular localization of Dax-1 is influenced by the presence of Ad4BP/SF-1, and that two regions of Dax-1 have important roles for this process.
authors.affiliation: Department of Developmental Biology, National Institute for Basic Biology, Myodaiji-cho, Okazaki 444-8585, Japan.
authors.forename: Kaname
authors.initials: K
authors.lastname: Kawajiri
authors.forename: Togo
authors.initials: T
authors.lastname: Ikuta
authors.forename: Taiga
authors.initials: T
authors.lastname: Suzuki
authors.forename: Masatomo
authors.initials: M
authors.lastname: Kusaka
authors.forename: Masami
authors.initials: M
authors.lastname: Muramatsu
authors.forename: Kenji
authors.initials: K
authors.lastname: Fujieda
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tachibana
authors.forename: Ken-Ichirou
authors.initials: K
authors.lastname: Morohashi
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology*; D000818:Animals; D001665:Binding Sites; D002467:Cell Nucleus / Q000502:physiology; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D051717:Fushi Tarazu Transcription Factors; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006367:HeLa Cells; D018398:Homeodomain Proteins; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D051379:Mice; D010902:Pituitary Gland / Q000196:embryology / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D054339:Steroidogenic Factor 1; D013329:Structure-Activity Relationship; D013347:Subcellular Fractions / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C539965:NR0B1 protein, human; C539966:Nr0b1 protein, mouse; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D054339:Steroidogenic Factor 1; D014157:Transcription Factors