A divergent role of COOH-terminal domains in Nurr1 and Nur77 transactivation
| Autor: | S O, Castillo, Q, Xiao, Z, Kostrouch, B, Dozin, V M, Nikodem |
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| Rok vydání: | 1998 |
| Předmět: |
Transcriptional Activation
Receptors Steroid Receptors Retinoic Acid Molecular Sequence Data Receptors Cytoplasmic and Nuclear Nerve Tissue Proteins Tretinoin Article Mice Structure-Activity Relationship Nuclear Receptor Subfamily 4 Group A Member 2 Nuclear Receptor Subfamily 4 Group A Member 1 Animals Amino Acid Sequence Cloning Molecular Alitretinoin Binding Sites Base Sequence Chromosome Mapping Nuclear Proteins 3T3 Cells DNA DNA-Binding Proteins Alternative Splicing Retinoid X Receptors Transcription Factors |
| Zdroj: | Gene expression. 7(1) |
| ISSN: | 1052-2166 |
| Popis: | Orphan nuclear receptors such as Nurr1 and Nur77 have conserved amino acid sequences in the zinc finger DNA binding domains and similar COOH-terminal regions, but have no known ligands. These receptors can bind DNA sequences (response elements) as monomers and can also heterodimerize with the retinoid X receptor to activate transcription. We report here the identification and initial characterization of a novel COOH-terminal truncated isoform of Nurr1, Nurr1a. Internal splicing of Nurr1 generates a frameshift such that a stop codon is prematurely encoded resulting in a naturally occurring COOH-terminal truncation. Embryonic and postnatal mouse brain showed both Nurr1 and Nurr1a mRNAs expressed during development. To characterize essential COOH-terminal elements that may be deleted from Nurr1a and determine function in putative ligand binding, we created COOH-terminal deletion mutants. Nurr1, Nur77, and 3′-truncated mutants bind in gel mobility shift assays to the monomeric Nur77 response element (B1A-RE). However, in transient transfection assays, a truncation of as little as 15 Nurr1 COOH-terminal amino acids diminished transcriptional activation of B1A-thymidine kinase-chloramphenicol acetyltransferase reporter. This result was not seen for a similar Nur77 deletion mutant, Nur77-586. Unlike full-length Nurr1 and Nur77, transactivation by Nur77-586 was not augmented in response to the presence of retinoid-like receptor and 9-cis-retinoic acid. Thus, the interaction of putative ligand binding and transactivation for Nurr1 and Nur77 may function differently. |
| Databáze: | OpenAIRE |
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