| Purification and Quality Control | The His-tag recombinant protein is purified by affinity chromatography in combination with FPLC columns. The purified LRH1 is greater than 95% homogeneous based on SDS-PAGE analysis. |
| Unit Definition (Activity) | 1 unit equals 1 nanogram of purified protein. 100 units are sufficient for a protein-protein interaction assay. |
| Applications | Recombinant LRH-1 can be used for protein-protein interaction 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 | Homo sapiens nuclear receptor subfamily 5, group A, member 2 (NR5A2), transcript variant 1; B1F; B1F2; CPF; FTF; FTZ-F1; FTZ-F1beta; hB1F; hB1F-2; LRH-1 and LRH1. |
| Protein Sequence | MSSNSDTGDL QESLKHGLTP IGAGLPDRHG SPIPARGRLV MLPKVETEAL GLARSHGEQG
QMPENMQVSQ FKMVNYSYDE DLEELCPVCG DKVSGYHYGL LTCESCKGFF KRTVQNNKRY
TCIENQNCQI DKTQRKRCPY CRFQKCLSVG MKLEAVRADR MRGGRNKFGP MYKRDRALKQ
QKKALIRANG LKLEAMSQVI QAMPSDLTIS SAIQNIHSAS KGLPLNHAAL PPTDYDRSPF
VTSPISMTMP PHGSLQGYQT YGHFPSRAIK SEYPDPYTSS PESIMGYSYM DSYQTSSPAS
IPHLILELLK CEPDEPQVQA KIMAYLQQEQ ANRSKHEKLS TFGLMCKMAD QTLFSIVEWA
RSSIFFRELK VDDQMKLLQN CWSELLILDH IYRQVVHGKE GSIFLVTGQQ VDYSIIASQA
GATLNNLMSH AQELVAKLRS LQFDQREFVC LKFLVLFSLD VKNLENFQLV EGVQEQVNAA
LLDYTMCNYP QQTEKFGQLL LRLPEIRAIS MQAEEYLYYK HLNGDVPYNN LLIEMLHAKR
A |
| Background | LRH-1 or HB1F for human B1-binding factor belongs to the fushi tarazu factor-1 (FTZ-F1) subfamily of orphan nuclear receptors and is closely related to steroidogenic factor-1. LRH1 contains a DNA-binding domain with 2 zinc finger motifs, an FTZ-F1 box, and a ligand-binding domain.(1) Cholesterol 7-alpha-hydroxylase is the first and rate-limiting enzyme in a pathway through which cholesterol is metabolized to bile acids. Elevated promoter-specific repressor protein (SHP) inactivates LRH1 by forming a heterodimeric complex that leads to promoter-specific repression of both CYP7A1 and SHP. These results revealed an elaborate autoregulatory cascade mediated by nuclear receptors for the maintenance of hepatic cholesterol catabolism. (2) LRH1 specifically binds and activates viral hepatitis B enhancer II, an essential element for the liver-specific regulation of hepatitis B virus gene expression. (1) CPF is a key regulator of human CYP7A gene expression in the liver. SHP1 represses expression of CYP7A1 by inhibiting the activity of LRH1 which regulates CYP7A1 expression positively. This bile acid-activated regulatory cascade provides a molecular basis for the coordinate suppression of CYP7A1 and other genes involved in bile acid biosynthesis. (3) |
| References | 1. Li, M. et al., J. (1998) Biol. Chem. 273: 29022-29031
2. Lu, T. T. et al., (2000) Molec. Cell 6: 507-515
3. Goodwin, B et al. (2000) Molec. Cell 6: 517-526 |
