Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The iso forms of gizzard actin present during chicken embryogenesis were analyzed by two-dimensional electrophoresis. During chick embryogenesis there are conspicuous changes in the content of the iso forms of actin. Gizzards from 8-day-old embryos contain almost exclusively beta-actin. After 8 days of embryonic age, there is a continuous increase in the amount of gamma-actin and an apparent decrease in the amount of beta-actin. These changes in the content of beta- and gamma-actin in gizzard tissue are paralleled by changes in the content of the corresponding mRNAs, as detected by the ability of the RNAs to direct the synthesis of these proteins in micrococcal nuclease-digested reticulocyte lysates. The correlation of the in vivo and in vitro experiments indicates that during chick embryogenesis there is a differential expression of the genes coding for the iso forms of gizzard actin and that this expression is controlled at the transcriptional level.
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PMID:Differential expression of gizzard actin genes during chick embryogenesis. 50 Jun 29

The chromatin structures of a variety of plasmids and plasmid constructions, transiently transfected into mouse Ltk- cells using the DEAE-dextran procedure, were studied by micrococcal nuclease digestion of nuclei and Southern hybridization. Although regularly arranged nucleosome-like particles clearly were formed on the transfected DNA, the nucleosome ladders, in some cases with 13-14 bands, were anomalous. Most often, a ladder of DNA fragments with lengths of approximately 300, 500, 700, 900 bp, etc. was generated. In contrast, typical 180-190 bp multiples were generated from bulk cellular or endogenous beta-actin gene chromatin. Very similar results were obtained with all DNA's transfected, and in a variety of cell lines, provided that plasmid replication did not occur. Additionally, after digestion of nuclei, about 90% of the chromatin fragments that contained transfected DNA sequences could not be solubilized at low ionic strength, in contrast with bulk cellular chromatin, suggesting association with nuclear structures or nuclear matrix. The remaining 10% of transfected DNA sequences, arising from soluble chromatin fragments, generated a typical nucleosome ladder. These results are consistent with the idea that assembly of atypical chromatin structures might be induced by proximity to elements of the nuclear pore complex or by nuclear compartmentalization.
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PMID:Micrococcal nuclease digestion of nuclei reveals extended nucleosome ladders having anomalous DNA lengths for chromatin assembled on non-replicating plasmids in transfected cells. 751 Mar 91

Transcriptional activation in eukaryotes is often accompanied by alterations to chromatin structure at specific regulatory sites while other genomic regions may remain unchanged. In this study, we have examined the correlation between expression and chromatin accessibility of the human CR2 gene in a panel of cell lines (U937, REH, Ramos, and Raji) using the CHART-PCR assay with the accessibility agent micrococcal nuclease (MNase). To validate the use of this assay for comparing multiple cell-types, we first tested a series of genomic regions to determine if we could observe consistent, site-specific levels of MNase chromatin accessibility. Promoter regions of the ubiquitously expressed genes GAPDH and beta-actin were similar and showed high accessibility to MNase digestion in each of the cell lines, while on the other hand, promoter regions of developmentally restricted genes PAX-7 and SP-A2 showed consistently reduced chromatin accessibility. Since CHART-PCR detected site-specific differences in chromatin accessibility in a manner that could be compared between cell-types, we next examined chromatin accessibility over the CR2 core promoter in the panel of cell lines representing either CR2 expressing or CR2 non-expressing cell-types. Our data revealed significantly enhanced accessibility over the -289 to -101 and the -115 to -12 regions of the CR2 promoter in expressing B-cells (Ramos, Raji) compared to non-expressing cells (U937, REH). Thus, CHART-PCR assays detected a correlation between chromatin accessibility and expression of the human CR2 gene, while the accessibility of other genomic regions was site-specific, but not altered between cell-types.
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PMID:Quantitative differences in chromatin accessibility across regulatory regions can be directly compared in distinct cell-types. 1816 59