Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Steroid receptor binding factor (RBF) was originally isolated from avian oviduct nuclear matrix. When bound to avian genomic DNA, RBF generates saturable high-affinity binding sites for the avian progesterone receptor (PR). Recent studies have shown that RBF binds to a 54 bp element in the 5'-flanking region of the progesterone-regulated avian c-myc gene, and nuclear matrix-like attachment sites flank the RBF element [Lauber et al. (1997) J. Biol. Chem. 272, 24657-24665]. In this paper, electrophoretic mobility shift assays (EMSAs) and S1 nuclease treatment are used to demonstrate that the RBF-maltose binding protei (MBP) fusion protein binds to single-stranded DNA of its element. Only the N-terminal domain of RBF binds the RBF DNA element as demonstrated by southwestern blot analyses, and by competition EMSAs between RBF-MBP and the N-terminal domain. Mass spectrometric analysis of the C-terminal domain of RBF demonstrates its potential to form noncovalent protein-protein interactions via a potential leucine-isoleucine zipperlike structure, suggesting a homo- and/or possible heterodimer structure in solution. These data support that the nuclear matrix binding site (acceptor site) for PR in the c-myc gene promoter is composed of RBF dimers bound to a specific single-stranded DNA element. The dimers of RBF are generated by C-terminal leucine zipper and the DNA binding occurs at the N-terminal parallel beta-sheet DNA binding motif. This complex is flanked by nuclear matrix attachment sites.
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PMID:Interactions of the nuclear matrix-associated steroid receptor binding factor with its DNA binding element in the c-myc gene promoter. 1065 41

The myc gene family, including c- and N-myc, is believed to play a critical role in the regulation of cell cycle and proliferation. The function of N-myc, in contrast to c-myc, is not clearly understood. Here we report that, using a N-myc expression vector in CAT and S1 nuclease protection assays, the N-myc protein trans-represses expression of the human N-myc, the mouse N-myc, and the human MHC class 1 antigen genes. The analysis of N-myc deletion mutants showed that the N-terminal region where there are amino acid sequences highly conserved in the myc family and the central region where the acidic amino acids are concentrated, are necessary for trans-repression activity. Also, the region near the C-terminus is relevant for DNA-protein and protein-protein interaction; in particular, the basic region, helix-loop-helix, and leucine zipper are important for activity.
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PMID:Determination of transrepression domains of the human N-myc protein. 2158 77