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)

Initiation of the immunoglobulin heavy chain switch DNA rearrangement event is thought to involve conversion of the target switch region DNA to an accessible state. Accessibility is likely to be mediated by the binding of regulatory proteins to sequences in or near switch regions. A DNase hypersensitivity assay was used to recognize possible regions of protein binding in the gamma 1 switch region of the B cell hybridoma 470.25. A strong DNase hypersensitive site was identified 5' of the tandemly repeated S gamma 1 sequences. Data from other laboratories suggest that this hypersensitive site is associated with switch recombination to gamma 1. However, the 470.25 cell does hypersensitive sites within the repetitive portion of the gamma 1 switch region was also identified. A gel retardation assay for protein--DNA interaction revealed a sequence present in several copies in the gamma 1 switch region that specifically binds nuclear proteins. This binding sequence, SG1BS, contains the octanucleotide sequence ATGCAAAA, a 7/8 match to the transcriptional enhancer octamer motif found in immunoglobulin promoters and the heavy chain enhancer. Binding competition studies of SG1BS demonstrate that both the octamer and flanking sequences are critical for binding. By size- and tissue-distribution, the factors that bind SG1BS are not distinguishable from the previously identified octamer-binding factors OTF-1 and OTF-2. The ability of proteins to bind the S gamma 1 octamer motif is increased 2.3-fold upon IL-4 induction of lipopolysaccharide-stimulated B cells.
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PMID:Nuclear protein binding to octamer motifs in the immunoglobulin gamma 1 switch region. 202 12

We have used DNAase I footprinting and the gel mobility shift assay to study proteins which bind to promoter elements located between -140 and -382 upstream of the human A gamma globin gene. Footprints are found with both erythroid and nonerythroid nuclear extracts at three sites: from -294 to -264, -242 to -227, and -189 to -172 from the transcription initiation site. An erythroid-specific footprint is identified from -194 to -189. We demonstrate that two known transcription factors, the ubiquitous octamer-binding protein OTF-1 and the erythroid regulatory factor NFE-1, bind to the -194 to -172 region and that their footprints overlap. Binding of OTF-1 to this region is reduced by a mutation at -175 associated with a form of non-deletion hereditary persistence of fetal hemoglobin. We conclude that OTF-1 may compete with NFE-1 for the -175 binding site, possibly functioning as a repressor of gamma globin transcription.
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PMID:Protein-DNA interactions upstream from the human A gamma globin gene. 233 86

The octamer-binding proteins present in HeLa cells, B-cells and malignant melanoma cells were compared by a gel-electrophoresis DNA-binding assay. Using an extract from the malignant melanoma cells a complex was formed using a variety of octamer containing probes that was distinct from those found using either a HeLa or B-cell extract. DNAase 1 footprints and methylation interference patterns of the melanoma-specific octamer-binding protein were indistinguishable from those obtained with the HeLa factor NF-A1, except for preferential binding of the melanoma-specific factor to DNA methylated at two G residues 16 base-pairs 3' to the octamer motif. Competition analyses using a variety of wild-type and mutant probes showed that mutations affecting binding of NF-A1 similarly affected binding of the melanoma octamer-binding factor. These data also revealed the extreme flexibility of the octamer-binding site, with one probe sharing only 4 bases with the 8 base consensus sequence binding efficiently.
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PMID:A distinct octamer-binding protein present in malignant melanoma cells. 326 9