Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have identified sequences responsible for the expression of the human glucocorticoid receptor gene (GR gene) using a set of 5' promoter deletion mutants in HeLa, human placenta, and human breast tumor (MCF-7) cells. The chimeric gene construct -892 5'-GAAGTGACACACTTC3' -878-CAT was sufficient for high level of expression in HeLa and placenta cells in culture. Deletion of palindromic sequences decreased levels of GR expression in these cells. By oligonucleotide-affinity chromatography with the palindromic glucocorticoid receptor enhancing factor-binding element (GREFE), we have isolated from human placenta nuclear extract two novel proteins glucocorticoid receptor enhancing factors 1 and 2 (GREF1 and GREF2), with apparent molecular masses of 80 and 62 kDa, respectively. These proteins, similar to the DNA-binding autoantigen Ku are, like Ku, heterodimers of polypeptide subunits p80 and p62, immunologically related to factors binding to proximal sequence element 1 in the promoter of small nuclear RNA (PSE1) and transferrin receptor enhancing factors. Both Ku80 and Ku70 polypeptides were present in high concentrations in human placenta and HeLa cells. In MCF-7 cells, however, only a high level of p62 was detected. While cotransfection of pcDNA-Ku80 with pHGR(-892 to -878)-CAT potentiated the expression of CAT, introduction of pcDNA-Ku70 did not affect the expression of CAT in transfected MCF-7 cells. UV cross-linking analysis showed that only GREF1 contacted DNA directly. Supershift assays with monoclonal antibodies Ab 111 (Ku80) or Ab N3H10 (Ku70) showed a direct interaction of GREF1 and GREF2 heterodimers with the palindrome. Partial peptide fingerprinting of GREF1 and GREF2 using alpha-chymotrypsin and immunoblotting with Ab 111 and Ab N3H10 confirmed their identities as Ku80 and Ku70, respectively.
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PMID:Expression of human glucocorticoid receptor gene and interaction of nuclear proteins with the transcriptional control element. 870 20

The activation domains of many transcription factors appear to exist naturally in an unfolded or only partially folded state. This seems to be the case for AF1/tau1, the major transactivation domain of the human glucocorticoid receptor. We show here that in buffers containing the natural osmolyte trimethylamine N-oxide (TMAO), recombinant AF1 folds into more a compact structure, as evidenced by altered fluorescence emission, circular dichroism spectra, and ultracentrifugal analysis. This conformational transition is cooperative, a characteristic of proteins folding to natural structures. The structure resulting from incubation in TMAO causes the peptide to resist proteolysis by trypsin, chymotrypsin, endoproteinase Arg-C and endoproteinase Gluc-C. Ultracentrifugation studies indicate that AF1/tau1 exists as a monomer in aqueous solution and that the presence of TMAO does not lead to oligomerization or aggregation. It has been suggested that recombinant AF1 binds both the ubiquitous coactivator CBP and the TATA box-binding protein, TBP. Interactions with both of these are greatly enhanced in the presence of TMAO. Co-immunoadsorption experiments indicate that in TMAO each of these and the coactivator SRC-1 are found complexed with AF1. These data indicate that TMAO induces a conformation in AF1/tau1 that is important for its interaction with certain co-regulatory proteins.
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PMID:The conformation of the glucocorticoid receptor af1/tau1 domain induced by osmolyte binds co-regulatory proteins. 1127 38


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