title: SmTR2/4, a Schistosoma mansoni homologue of TR2/TR4 orphan nuclear receptor.
abstract: cDNA clones encoding a Schistosoma mansoni homologue of the TR2/TR4 group of nuclear receptors, SmTR2/4, were identified by screening an adult female worm cDNA library. SmTR2/4 is a 1,943 amino acid protein, the largest member of the TR2/TR4 group of nuclear receptors and also the largest nuclear receptor reported to date. SmTR2/4 retains a typical domain organisation of nuclear receptors exhibiting 69-77% sequence identity in the DNA binding domain and 16-22% sequence identity in the ligand binding domain compared with its orthologues. SmTR2/4 contains a large A/B domain and hinge region. SmTR2/4 also contains a 100 amino acid F domain, which is absent from its orthologues. SmTR2/4 mRNA is expressed in every stage of the S. mansoni life cycle, exhibiting an elevated expression level in cercariae. Western blot analysis identified two forms of SmTR2/4 protein in adult worms. Our in vitro DNA binding assay showed that SmTR2/4 binds to the DR-3 consensus hormone response element, suggesting a functional conservation among the TR2/TR4 group members in terms of DNA binding specificity. A yeast-based transactivation assay demonstrated that the A/B domain, F domain and N-terminal part of the hinge region in SmTR2/4, when tethered to a GAL4 DNA binding domain, exhibited an autonomous transcription activation function.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, State University of New York, Buffalo, NY 14214, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Hu
authors.forename: Wenjie
authors.initials: W
authors.lastname: Wu
authors.forename: Edward G
authors.initials: EG
authors.lastname: Niles
authors.forename: Philip T
authors.initials: PT
authors.lastname: LoVerde
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D015870:Gene Expression; D015723:Gene Library; D017238:Genes, Helminth; D008018:Life Cycle Stages; D008969:Molecular Sequence Data; D057107:Nuclear Receptor Subfamily 2, Group C, Member 1; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics*; D011988:Receptors, Thyroid Hormone / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012550:Schistosoma mansoni / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
chemical_list: D057107:Nuclear Receptor Subfamily 2, Group C, Member 1; D018160:Receptors, Cytoplasmic and Nuclear; D011988:Receptors, Thyroid Hormone