Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In herpes simplex virus-infected cells, gene expression is tightly regulated. In this review, we compare the properties of two trans-activating factors which regulate the expression of viral genes. The first, alpha trans-inducing factor (alpha TIF) is a structural component which induces the 5 alpha genes, the first set of genes transcribed after infection. Alpha TIF requires for induction a cis-acting site present in promoter-regulatory domains of all alpha genes. The cis site binds 2 host proteins, alpha H1 and alpha H2-alpha H3. These host proteins have a maximum bound molecular weight of 110,000 and 64,000, respectively. DNase 1 protection assays indicate that alpha H1 protects the entire cis site, whereas alpha H2-alpha H3 binds the 3' domain of the cis site. The methylation interference assays indicate that the contact points of alpha H1 and alpha H2-H3 are at the 5' and 3' termini of the cis site, respectively. Both proteins can bind to the cis site concurrently. Alpha TIF does not bind directly to DNA but was shown to be present in DNA-protein complexes. The binding of alpha TIF to these DNA-protein complexes requires the participation of alpha H1. In contrast to alpha TIF, the product of the alpha 4 gene, a protein 163,000 in apparent molecular weight binds to DNA directly and regulates genes both positively and negatively. The data indicate that alpha 4 protein can bind to at least 2 binding sites differing in nucleotide sequence and which can be present in promoters, across the transcription initiation sites, and in 5' transcribed non-coding sequences. The regulatory functions of the alpha 4 protein may reflect both the nature and location of the binding site. The biological implications of the viral trans-acting proteins are discussed.
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PMID:The trans-activation of herpes simplex virus gene expression: comparison of two factors and their cis sites. 285 7

The herpes simplex virus 1 genes form at least five groups (alpha, beta 1, beta 2, gamma 1, and gamma 2) whose expression is coordinately regulated and sequentially ordered in a cascade fashion. In productively infected cells, the alpha genes are expressed first, and a virion protein, the alpha-trans-inducing factor (alpha-TIF), acts in trans to enhance their expression. Induction of the alpha genes by alpha-TIF requires the presence of a trans-induction cis-acting site (alpha-TIC), and one to three homologs of the alpha-TIC sequence are contained in the regulatory domains of all alpha genes. We report that small DNA fragments from regulatory domains of alpha 0, alpha 4, and alpha 27 genes containing alpha-TIC homologs formed complexes with host but not viral proteins. DNase protection studies indicated that the major host protein complex alpha-H1 detected in DNA gel retardation assays bound asymmetrically across the alpha-TIC site. All DNA fragments containing alpha-TIC homologs, but not those lacking the homolog, competed for the binding of this complex. The location of the binding site of the other host proteins is not yet known. Simian virus 40 DNA fragments containing a homolog of the alpha-TIC sequence also competed with herpes simplex virus DNA fragments carrying authentic alpha-TIC homologs for the alpha-H1 protein complex.
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PMID:Host cell proteins bind to the cis-acting site required for virion-mediated induction of herpes simplex virus 1 alpha genes. 302 64

Previously we have shown that the RNA polymerase I (Pol I)-specific transcription factor UBF stimulates transcription by both facilitating transcription complex formation and by relieving repression exerted by a negative-acting factor which competes for binding of the murine factor TIF-IB to the ribosomal gene promoter (1). We have purified and functionally characterized this repressor protein from Ehrlich ascites cells. The final preparation contained two polypeptides with molecular masses of 75 and 90 kDa, respectively. Both polypeptides interact with the rDNA promoter as revealed by UV-crosslinking experiments. The specificity of binding to the ribosomal gene promoter was demonstrated in an electrophoretic mobility shift assay and by DNase footprinting. The biochemical properties of this negative-acting factor closely resemble those of the Ku antigen, a human nuclear DNA-binding heterodimer which is the target of autoantibodies in several autoimmune diseases. Anti-Ku antibodies precipitate the repressor activity and overcome transcription inhibition. The data demonstrate that regulation of Pol I gene transcription may involve an antirepression mechanism as already documented for Pol II genes and suggest that Ku protein may be causally involved in repressor-mediated down regulation of rRNA synthesis.
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PMID:The nucleolar transcription activator UBF relieves Ku antigen-mediated repression of mouse ribosomal gene transcription. 850 46