| Purification and Quality Control | The His-tag recombinant protein is purified by affinity chromatography in combination with FPLC columns. The purified Thyroid Hormone Receptor beta 1 isoform is greater than 95% homogeneous based on SDS-PAGE analysis. | | Unit Definition (Activity) | 1 unit equals 1 nanogram of purified protein. 1 unit is sufficient for a gel mobility shift assay in a 20 µl reaction; 100 units are sufficient for protein-protein interaction assays. | | Applications | TR has been applied in reconstituted in vitro transcription assays, protein-protein interactions assays and chromatin remodeling assays. | | Formulation and Storage | The protein is in 20mM Tris-HCl pH7.9,100mM NaCl, 0.2mM EDTA, 1mM DTT and 20% glycerol. Stored at -70°C before use. Avoid repeated freeze thaw cycles. | | Synonym | ERBA-BETA; ERBA2; GRTH; NR1A2; PRTH; THR1; THRB1; THRB2 | | Protein Sequence | MTPNSMTENG LTAWDKPKHC PDREHDWKLV GMSEACLHRK SHSERRSTLK NEQSSPHLIQ
TTWTSSIFHL DHDDVNDQSV SSAQTFQTEE KKCKGYIPSY LDKDELCVVC GDKATGYHYR
CITCEGCKGF FRRTIQKNLH PSYSCKYEGK CVIDKVTRNQ CQECRFKKCI YVGMATDLVL
DDSKRLAKRK LIEENREKRR REELQKSIGH KPEPTDEEWE LIKTVTEAHV ATNAQGSHWK
QKRKFLPEDI GQAPIVNAPE GGKVDLEAFS HFTKIITPAI TRVVDFAKKL PMFCELPCED
QIILLKGCCM EIMSLRAAVR YDPESETLTL NGEMAVTRGQ LKNGGLGVVS DAIFDLGMSL
SSFNLDDTEV ALLQAVLLMS SDRPGLACVE RIEKYQDSFL LAFEHYINYR KHHVTHFWPK LLMKVTDLRM IGACHASRFL HMKVECPTEL FPPLFLEVFE D | | Background | Nuclear receptors form the largest known family of transcription factors and have a crucial role in nearly all aspects of vertebrate development and adult physiology by transducing the effects of hormones into transcriptional responses (1). The family is defined by two domains: (a) the central, highly conserved, DNA-binding domain (DBD) of approximately 66 amino acids, and (b) the C-terminal, structurally conserved, ligand-binding domain (LBD) of approximately 250 amino acids (2, 3). The amino-terminal regions are least conserved among nuclear receptor sequences. This domain is highly divergent between TRα and TRβ isoforms, which suggests differential roles in transcriptional regulation. In addition, alternative splicing of the TRα gene generates two isoforms, TRα1 and TRα2 with completely different amino-terminal domains (4). Unliganded TR inhibits the formation of a functional pre-initiation complex, through direct interaction with TBP and transcription factor IIB (5-7). In addition, in the absence of ligand, TR has been shown to repress transcription through recruitment of a corepressor complex, which also includes Sin3A and histone deacetylase (8, 9). Ligand binding releases the corepressor complex and recruits a coactivator complex that includes multiple histone acetyltransferases, including a steroid receptor family coactivator, p300/CREB-binding protein–associated factor (PCAF), and CREB binding protein (CBP) (10-14). | | References | 1. Mangelsdorf, D. J., et al., (1995) Cell 83, 835–839
2. Glass, C. K. (1994) Endocrinol. Rev. 15, 391–407
3. Moras, D., et al., (1998) Curr. Opin. Cell Biol. 10, 384-391
4. Lazar M.A. (1993) Endocr. Rev. 14, 184–193
5. Fondell J.D. et al., (1993) Genes Dev. 7, 1400–1410
6. Fondell J.D., et al., (1996) Mol. Cell Biol. 16, 281–287
7. Baniahmad A., et al., (1993) Proc. Natl. Acad. Sci. USA 90, 8832–8836
8. Zhang X.J.M., et al., (1996) J. Biol. Chem. 271, 14825–14833
9. Heinzel, T., et al., (1997) Nature 387, 43-48
10. Onate, S. A., et al., (1995) Science 270, 1354-1357
11. Kamei, Y., et al., (1996) Cell 85, 403-414
12. Blanco, J.C., et al., (1998) Genes Dev. 12, 1638-1651
13. Fondell, J.D., et al., (1996) Proc. Natl. Acad. Sci. USA 93, 8329-8333
14. Wolffe, A., et al., (1997) Genes Cells 2, 291-302 | | Image of SDS-PAGE /Western-blot |  |
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