title: Molecular cloning and characterization of chicken orphan nuclear receptor cTR2.
abstract: Orphan nuclear receptors belong to the nuclear receptor superfamily of liganded transcription factors, whose ligands either do not exist or remain to be identified. We report here the cloning and characterization of the chicken orphan nuclear receptor, cTR2 (chicken testicular receptor 2). The cTR2 gene encodes a protein of 569 amino acids which shows approximately 72% overall identity with TR2 (NR2C1) and 95% identity in the DNA-binding domain (DBD). The cTR2 gene is expressed in almost all adult tissues and embryonic stages examined unlike its mammalian relative TR2, which is specifically expressed in testis. Electrophoretic mobility shift assays demonstrate that cTR2 binds the canonical direct repeat DNA recognition sequences spaced by one, four, and five nucleotides (DR1, DR4, and DR5), and in consistence with the results with canonical DNA-binding sequences, cTR2 forms specific DNA-protein complex with chicken phenobarbital response elements containing DR4 motifs. Both in vitro and in vivo interaction studies demonstrate that cTR2 forms homodimer. Moreover, transient transfection studies reveal its capability to transactivate canonical DR1, DR4, and DR5 sequences and the constitutive activity of cTR2 is mapped to the N-terminal region of this orphan receptor. Finally, cTR2 represses transactivation of estrogen receptor in a dose-dependent manner.
authors.affiliation: Hormone Research Center, Chonnam National University, 500-757 Kwangju, Republic of Korea.
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Sanyal
authors.forename: Chirstoph
authors.initials: C
authors.lastname: Handschin
authors.forename: Michael
authors.initials: M
authors.lastname: Podvinec
authors.forename: Kwang-Hoon
authors.initials: KH
authors.lastname: Song
authors.forename: Han-Jong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Joon-Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Seo
authors.forename: Sung-A
authors.initials: SA
authors.lastname: Kim
authors.forename: Hyuk-Bang
authors.initials: HB
authors.lastname: Kwon
authors.forename: Keesook
authors.initials: K
authors.lastname: Lee
authors.forename: Won-Sun
authors.initials: WS
authors.lastname: Kim
authors.forename: Urs A
authors.initials: UA
authors.lastname: Meyer
authors.forename: Hueng-Sik
authors.initials: HS
authors.lastname: Choi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D057107:Nuclear Receptor Subfamily 2, Group C, Member 1; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics* / Q000378:metabolism; D011988:Receptors, Thyroid Hormone / Q000235:genetics* / Q000378:metabolism; D014018:Tissue Distribution; D015533:Transcriptional Activation
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D057107:Nuclear Receptor Subfamily 2, Group C, Member 1; D011960:Receptors, Estrogen; D011987:Receptors, Steroid; D011988:Receptors, Thyroid Hormone