scholarly journals In vivo DNase I sensitivity of the Streptomyces coelicolor chromosome correlates with gene expression: implications for bacterial chromosome structure

2006 ◽  
Vol 34 (19) ◽  
pp. 5395-5401 ◽  
Author(s):  
Michael McArthur ◽  
Mervyn Bibb
Keyword(s):  
Gene Expression ◽  
Chromosome Structure ◽  
Streptomyces Coelicolor ◽  
Dnase I ◽  
Bacterial Chromosome ◽  
Dnase I Sensitivity

scholarly journals Gamma rays and bleomycin nick DNA and reverse the DNase I sensitivity of beta-globin gene chromatin in vivo.

1987 ◽  
Vol 7 (5) ◽  
pp. 1917-1924 ◽  
Author(s):  
B Villeponteau ◽  
H G Martinson
Keyword(s):  
Globin Gene ◽  
Dnase I ◽  
Globin Genes ◽  
Torsional Stress ◽  
Beta Globin ◽  
Cell Penetration ◽  
Dnase I Sensitivity ◽  
Chicken Erythrocytes ◽  
Active Genes

The active beta-globin genes in chicken erythrocytes, like all active genes, reside in large chromatin domains which are preferentially sensitive to digestion by DNase I. We have recently proposed that the special structure of chromatin in active domains is maintained by torsional stress in the DNA (Villeponteau et al., Cell 39:469-478, 1984). This hypothesis predicts that nicking of the DNA within any such chromosomal domain in vivo will relax the DNA and lead to loss of the special DNase I-sensitive state. Here we have tested this prediction by using gamma irradiation and bleomycin treatment to cleave DNA within intact chicken embryo erythrocytes. Both treatments cause reversal of DNase I sensitivity. Moreover, reversal occurs at approximately one nick per 150 kilobase pairs for both agents despite their entirely unrelated modes of cell penetration and DNA attack. These results suggest that the domain of DNase I sensitivity surrounding the beta-globin genes comprises 150 kilobase pairs of chromatin under torsional stress and that a single DNA nick in this region is sufficient to reverse the DNase I sensitivity throughout the entire domain.

Tissue-Specific in Vivo Inhibition of DNase I Gene Expression by Somatostatin

2001 ◽  
Vol 283 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Toshihiro Yasuda ◽  
Haruo Takeshita ◽  
Misuzu Ueki ◽  
Reiko Iida ◽  
Tamiko Nakajima ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dnase I ◽  
Tissue Specific ◽  
I Gene

Genome-scale mapping of DNase I sensitivity in vivo using tiling DNA microarrays

2006 ◽  
Vol 3 (7) ◽  
pp. 511-518 ◽  
Author(s):  
Peter J Sabo ◽  
Michael S Kuehn ◽  
Robert Thurman ◽  
Brett E Johnson ◽  
Ericka M Johnson ◽  
...  
Keyword(s):  
Dna Microarrays ◽  
Dnase I ◽  
Dnase I Sensitivity ◽  
Genome Scale

scholarly journals Role of the Promoter in Maintaining Transcriptionally Active Chromatin Structure and DNA Methylation Patterns In Vivo

2003 ◽  
Vol 23 (12) ◽  
pp. 4150-4161 ◽  
Author(s):  
Sung-Hae Lee Kang ◽  
Christine Mione Kiefer ◽  
Thomas P. Yang
Keyword(s):  
Dna Methylation ◽  
Chromatin Structure ◽  
Dnase I ◽  
Dnase I Hypersensitivity ◽  
Translation Start ◽  
Dnase I Sensitivity ◽  
Active Transcription ◽  
Methylation Patterns

ABSTRACT Establishment and maintenance of differential chromatin structure between transcriptionally competent and repressed genes are critical aspects of transcriptional regulation. The elements and mechanisms that mediate formation and maintenance of these chromatin states in vivo are not well understood. To examine the role of the promoter in maintaining chromatin structure and DNA methylation patterns of the transcriptionally active X-linked HPRT locus, 323 bp of the endogenous human HPRT promoter (from position −222 to +102 relative to the translation start site) was replaced by plasmid sequences by homologous recombination in cultured HT-1080 male fibrosarcoma cells. The targeted cells, which showed no detectable HPRT transcription, were then assayed for effects on DNase I hypersensitivity, general DNase I sensitivity, and DNA methylation patterns across the HPRT locus. In cells carrying the deletion, significantly diminished DNase I hypersensitivity in the 5′ flanking region was observed compared to that in parental HT-1080 cells. However, general DNase I sensitivity and DNA methylation patterns were found to be very similar in the mutated cells and in the parental cells. These findings suggest that the promoter and active transcription play a relatively limited role in maintaining transcriptionally potentiated epigenetic states.

Epigenetics of Cellular Memory: Insights from the Chromatin Accessibility Landscape of the Mitotic Genome

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4342-4342
Author(s):  
Chris C.S. Hsiung ◽  
Christapher Morrissey ◽  
Maheshi Udugama ◽  
Christopher Frank ◽  
Cheryl A. Keller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Transcription Factors ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Dnase I ◽  
Specific Gene ◽  
Tissue Specific ◽  
Dnase I Sensitivity ◽  
Mitotic Chromatin

Abstract Normal development requires the coordination of cell cycle progression and gene expression to produce physiologically appropriate cell numbers of various lineages. The concomitant dysregulation of these two cellular programs is central to many malignant and non-malignant hematologic diseases, yet researchers still lack clear, general principles of how intrinsic properties of cell division could influence transcriptional regulation. Mitosis is a unique phase of the cell cycle that dramatically disrupts transcription: chromosomes condense to form microscopically recognizable structures, the nucleus is disassembled, RNA synthesis ceases, and the transcription machinery and many transcription factors are evicted from mitotic chromatin. How cells “remember” tissue-specific transcriptional programs through mitotic divisions remains largely unknown. Some transcription factors, including the erythroid master regulator, GATA1, and certain chromatin features are known to remain associated with DNA during mitosis. These molecular entities have been proposed to serve as mitotic “bookmarks” -- molecules that store gene regulatory information at individual loci through mitosis. However, we have limited knowledge of the composition, mechanism and function of mitotic bookmarks. In this context, chromatin structure deserves special consideration, as chromosome condensation during mitosis could potentially hinder transcription factor binding. To obtain the first genome-wide view of chromatin accessibility during mitosis, we mapped the DNase I sensitivity of the interphase versus mitotic genome in two maturation stages in a murine erythroblast cell line, G1E. Despite microscopic condensation of chromosomes during mitosis, we found that DNase I sensitivity is extensively preserved throughout the mappable genome, indicating that mitotic chromatin is not as condensed as commonly presumed. Individual genes and cis-regulatory elements can maintain all, part of, or none of its interphase accessibility during mitosis, demonstrating that accessibility of mitotic chromatin is locally specified. Promoters generally maintain accessibility during mitosis; moreover, promoters with the highest degree of accessibility preservation in mitosis in G1E cells tend to also be accessible across many murine tissues in interphase. In contrast to promoters, we found that enhancer accessibility is preferentially lost during mitosis, raising the possibility that memory of enhancer regulation may be altered during mitosis. Since enhancers play crucial roles in specifying tissue-specific gene expression patterns, we propose that this phase of the cell cycle may be especially susceptible to resetting of transcriptional programs. This hypothesis is supported by our preliminary results that revealed aberrant RNA polymerase II re-engagement with the genome and transcript production in early G1. Thus, mitosis could be a source of gene expression heterogeneity, with potential implications for cell fate transitions in proliferative cells, such as during stem cell lineage commitment, experimental reprogramming, and tumorigenesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals Nucleosomes and regulation of gene expression. Structure of the HIV-1 5'LTR.

1998 ◽  
Vol 45 (1) ◽  
pp. 209-219 ◽  
Author(s):  
P Widłak ◽  
W T Garrard
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Chromatin Remodeling ◽  
Binding Sites ◽  
Regulation Of Gene Expression ◽  
Dnase I ◽  
Chromatin Assembly ◽  
Hypersensitive Sites ◽  
Hiv 1

Packaging of DNA into chromatin adds complexity to the problem of regulation of gene expression. Nucleosomes affect the accessibility of transcription factors to occupy their binding sites in chromatin of eukaryotic cells. The disruption of nucleosome structure within the enhancer/promoter region of the integrated HIV-1 proviral genome is an instructive example of a chromatin remodeling process during transcriptional activation. To investigate the mechanism responsible for generating nuclease hypersensitive sites that exist in vivo in the promoter/enhancer region of the 5'LTR (long terminal repeat) of integrated HIV-1 we have utilized an in vitro chromatin assembly system with Xenopus oocyte extracts. Chromatin assembly in the presence of Sp1 and NFkappaB transcription factors induces DNase I hypersensitive sites on either side of their binding sites and positions the adjacent nucleosomes. This structure can also be formed in a factor-induced, ATP-dependent chromatin remodeling process and closely resembles the in vivo chromatin structure. The DNase I hypersensitive sites that form within the HIV LTR are probably histone-free and remain after removal of transcription factors.

scholarly journals Spatial control of gene expression in flies using bacterially derived binary transactivation systems

2020 ◽  
Author(s):  
Stephanie Gamez ◽  
Luis C. Vesga ◽  
Stelia C. Mendez-Sanchez ◽  
Omar S. Akbari
Keyword(s):  
Gene Expression ◽  
Pseudomonas Putida ◽  
Caulobacter Crescentus ◽  
Streptomyces Coelicolor ◽  
Molecular Genetic ◽  
Genetic Studies ◽  
Control Of Gene Expression ◽  
Multiple Systems

AbstractControlling gene expression is an instrumental tool for biotechnology, as it enables the dissection of gene function, affording precise spatial-temporal resolution. To generate this control, binary transactivational systems have been used employing a modular activator consisting of a DNA binding domain(s) fused to activation domain(s). For fly genetics, many binary transactivational systems have been exploited in vivo; however as the study of complex problems often requires multiple systems that can be used in parallel, there is a need to identify additional bipartite genetic systems. To expand this molecular genetic toolbox, we tested multiple bacterially-derived binary transactivational systems in Drosophila melanogaster including the p-CymR operon from Pseudomonas putida, PipR operon from Streptomyces coelicolor, TtgR operon from Pseudomonas putida, and the VanR operon from Caulobacter crescentus. Our work provides the first characterization of these systems in an animal model in vivo. For each system we demonstrate robust tissue-specific spatial transactivation of reporter gene expression, enabling future studies to exploit these transactivational systems for molecular genetic studies.

Gamma rays and bleomycin nick DNA and reverse the DNase I sensitivity of beta-globin gene chromatin in vivo

1987 ◽  
Vol 7 (5) ◽  
pp. 1917-1924
Author(s):  
B Villeponteau ◽  
H G Martinson
Keyword(s):  
Globin Gene ◽  
Dnase I ◽  
Globin Genes ◽  
Torsional Stress ◽  
Beta Globin ◽  
Cell Penetration ◽  
Dnase I Sensitivity ◽  
Chicken Erythrocytes ◽  
Active Genes

The active beta-globin genes in chicken erythrocytes, like all active genes, reside in large chromatin domains which are preferentially sensitive to digestion by DNase I. We have recently proposed that the special structure of chromatin in active domains is maintained by torsional stress in the DNA (Villeponteau et al., Cell 39:469-478, 1984). This hypothesis predicts that nicking of the DNA within any such chromosomal domain in vivo will relax the DNA and lead to loss of the special DNase I-sensitive state. Here we have tested this prediction by using gamma irradiation and bleomycin treatment to cleave DNA within intact chicken embryo erythrocytes. Both treatments cause reversal of DNase I sensitivity. Moreover, reversal occurs at approximately one nick per 150 kilobase pairs for both agents despite their entirely unrelated modes of cell penetration and DNA attack. These results suggest that the domain of DNase I sensitivity surrounding the beta-globin genes comprises 150 kilobase pairs of chromatin under torsional stress and that a single DNA nick in this region is sufficient to reverse the DNase I sensitivity throughout the entire domain.

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