Mad1 influences interphase nucleoplasm organization and chromatin regulation in
            Drosophila

The Drosophila Mad1 spindle checkpoint protein helps organize several nucleoplasmic components, and flies lacking Mad1 present changes in gene expression reflecting altered chromatin conformation. In interphase, checkpoint protein Mad1 is usually described as localizing to the inner nuclear envelope by binding the nucleoporin Tpr, an interaction believed to contribute to proper mitotic regulation. Whether Mad1 has other nuclear interphase functions is unknown. We found in Drosophila that Mad1 is present in nuclei of both mitotic and postmitotic tissues. Three proteins implicated in various aspects of chromatin organization co-immunoprecipitated with Mad1 from fly embryos: Mtor/Tpr, the SUMO peptidase Ulp1 and Raf2, a subunit of a Polycomb-like complex. In primary spermatocytes, all four proteins colocalized in a previously undescribed chromatin-associated structure called here a MINT (Mad1-containing IntraNuclear Territory). MINT integrity required all four proteins. In mad1 mutant spermatocytes, the other proteins were no longer confined to chromatin domains but instead dispersed throughout the nucleoplasm. mad1 flies also presented phenotypes indicative of excessive chromatin of heterochromatic character during development of somatic tissues. Together these results suggest that Drosophila Mad1, by helping organize its interphase protein partners in the nucleoplasm, contributes to proper chromatin regulation.

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Setting up and maintaining differential insulators and boundaries for genomic imprinting

Biochemistry and Cell Biology ◽

10.1139/o11-043 ◽

2011 ◽

Vol 89 (5) ◽

pp. 469-478 ◽

Cited By ~ 15

Author(s):

Adele Murrell

Keyword(s):

Gene Expression ◽

Regulatory Elements ◽

Imprinted Genes ◽

Chromatin Conformation ◽

Cell Lineages ◽

Somatic Tissues ◽

Gene Regulatory Elements ◽

Nuclear Environment ◽

Parent Of Origin ◽

Gene Regulatory

It is becoming increasingly clear that gene expression is strongly regulated by the surrounding chromatin and nuclear environment. Gene regulatory elements can influence expression over long distances and the genome needs mechanisms whereby transcription can be contained. Our current understanding of the mechanisms whereby insulator/boundary elements organise the genome into active and silent domains is based on chromatin looping models that separate genes and regulatory elements. Imprinted genes have parent-of-origin specific chromatin conformation that seems to be maintained in somatic tissues and reprogrammed in the germline. This review focuses on the proteins found to be present at insulator/boundary sequences at imprinted genes and examines the experimental evidence at the IGF2-H19 locus for a model in which CTCF or other proteins determine primary looping scaffolds that are maintained in most cell lineages and speculates how these loops may enable dynamic secondary associations that can activate or silence genes.

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Compound Symbiosis in Peridinium Balticum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072940 ◽

1973 ◽

Vol 31 ◽

pp. 500-501

Author(s):

R. N. Tomas

Keyword(s):

Endoplasmic Reticulum ◽

Nuclear Envelope ◽

The Other ◽

Exact Nature ◽

Symbiotic Relationship

Peridinium balticum appears to be unusual among the dinoflagellates in that it possesses two DNA-containing structures as determined by histochemical techniques. Ultrastructurally, the two dissimilar nuclei are contained within different protoplasts; one of the nuclei is characteristically dinophycean in nature, while the other is characteristically eucaryotic. The chloroplasts observed within P. balticum are intrinsic to an eucaryotic photosynthetic endosymbiont and not to the dinoflagellate. These organelles are surrounded by outpocketings of endoplasmic reticulum which are continuous with the eucaryotic nuclear envelope and are characterized by thylakoids composed of three apposed lamellae. Girdle lamellae and membranebounded interlamellar pyrenoids are also present. Only the plasmalemma of the endosymbiont segregates its protoplast from that of the dinophycean cytoplasm. The exact nature of this symbiotic relationship is at present not known.

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Reparação óssea no implante dental

Full Dentistry in Science ◽

10.24077/2020;1245-6366 ◽

2020 ◽

Vol 12 (45) ◽

pp. 63-66

Author(s):

Halim Nagem Filho ◽

Reinaldo Francisco Maia ◽

Reinaldo Missaka ◽

Nasser Hussein Fares

Keyword(s):

Gene Expression ◽

Titanium Surface ◽

Close Contact ◽

The Other ◽

Main Function ◽

Indirect Interaction ◽

M2 Macrophages ◽

Activated Macrophages ◽

M1 Macrophages ◽

High Production

The osseointegration is the stable and functional union between the bone and a titanium surface. A new bone can be found on the surface of the implant about 1 week after its installation; the bone remodeling begins between 6 and 12 weeks and continues throughout life. After the implant insertion, depending on the energy of the surface, the plasma fluid immediately adheres, in close contact with the surface, promoting the adsorption of proteins and inducing the indirect interaction of the cells with the material. Macrophages are cells found in the tissues and originated from bone marrow monocytes. The M1 macrophages orchestrate the phagocytic phase in the inflammatory region and also produce inflammatory cytokines involved with the chronic inflammation and the cleaning of the wound and damaged tissues from bacteria. On the other hand, alternative-activated macrophages (M2) are activated by IL-10, the immune complex. Its main function consists on regulating negatively the inflammation through the secretion of the immunosuppressant IL-10. The M2 macrophages present involvement with the immunosuppression, besides having a low capacity for presenting antigens and high production of cytokines; these can be further divided into M2a, M2b, and M2c, based on the gene expression profile.

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Analysis of the Mechanism by Which Glucose Inhibits Maltose Induction of MAL Gene Expression in Saccharomyces

Genetics ◽

10.1093/genetics/154.1.121 ◽

2000 ◽

Vol 154 (1) ◽

pp. 121-132

Author(s):

Zhen Hu ◽

Yingzi Yue ◽

Hua Jiang ◽

Bin Zhang ◽

Peter W Sherwood ◽

...

Keyword(s):

Gene Expression ◽

Glucose Repression ◽

Protein A ◽

The Other ◽

Maltose Permease ◽

Inducer Exclusion ◽

Glucose Inhibition ◽

Independent Mechanism ◽

Mal Genes

Abstract Expression of the MAL genes required for maltose fermentation in Saccharomyces cerevisiae is induced by maltose and repressed by glucose. Maltose-inducible regulation requires maltose permease and the MAL-activator protein, a DNA-binding transcription factor encoded by MAL63 and its homologues at the other MAL loci. Previously, we showed that the Mig1 repressor mediates glucose repression of MAL gene expression. Glucose also blocks MAL-activator-mediated maltose induction through a Mig1p-independent mechanism that we refer to as glucose inhibition. Here we report the characterization of this process. Our results indicate that glucose inhibition is also Mig2p independent. Moreover, we show that neither overexpression of the MAL-activator nor elimination of inducer exclusion is sufficient to relieve glucose inhibition, suggesting that glucose acts to inhibit induction by affecting maltose sensing and/or signaling. The glucose inhibition pathway requires HXK2, REG1, and GSF1 and appears to overlap upstream with the glucose repression pathway. The likely target of glucose inhibition is Snf1 protein kinase. Evidence is presented indicating that, in addition to its role in the inactivation of Mig1p, Snf1p is required post-transcriptionally for the synthesis of maltose permease whose function is essential for maltose induction.

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Activation of the lac Repressor in the Transgenic Mouse

Genetics ◽

10.1093/genetics/147.1.297 ◽

1997 ◽

Vol 147 (1) ◽

pp. 297-304

Author(s):

Heidi Scrable ◽

Peter J Stambrook

Keyword(s):

Copy Number ◽

Methylation Status ◽

Lac Repressor ◽

The Other ◽

Lac Operon ◽

Normal Process ◽

Divergent Sequence ◽

Somatic Tissues ◽

New Material ◽

Bacterial Sequence

Abstract We have introduced sequences encoding the lac repressor of Escherichia coli into the genome of the mouse. One sequence was derived from the bacterial lac operon and the other was created by reencoding the amino acid sequence of lacI with mammalian codons. Both versions are driven by an identical promoter fragment derived from the human β-actin locus and were microinjected into genetically identical pronuclear stage embryos. All transgenes utilizing the bacterial coding sequence were transcriptionally silent in all somatic tissues tested. The sequence re-encoded with mammalian codons was transcriptionally active at all transgene loci and expressed ubiquitously. Using methylation-sensitive enzymes, we have determined the methylation status of lac repressor transgenes encoded by either the bacterial or mammalian sequence. The highly divergent bacterial sequence was hypermethylated at all transgene loci, while the mammalian sequence was only hypermethylated at a high copy number locus. This may reflect a normal process that protects the genome from acquiring new material that has an abnormally divergent sequence or structure.

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What Are the Potential Roles of Nuclear Perlecan and Other Heparan Sulphate Proteoglycans in the Normal and Malignant Phenotype

International Journal of Molecular Sciences ◽

10.3390/ijms22094415 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4415

Author(s):

Anthony J. Hayes ◽

James Melrose

Keyword(s):

Gene Expression ◽

Nuclear Envelope ◽

Annulus Fibrosus ◽

Heparan Sulphate ◽

Cell Types ◽

Malignant Cell ◽

Cytoskeletal Proteins ◽

Nucleus Pulposus Cells ◽

Malignant Phenotype ◽

Heparan Sulphate Proteoglycans

The recent discovery of nuclear and perinuclear perlecan in annulus fibrosus and nucleus pulposus cells and its known matrix stabilizing properties in tissues introduces the possibility that perlecan may also have intracellular stabilizing or regulatory roles through interactions with nuclear envelope or cytoskeletal proteins or roles in nucleosomal-chromatin organization that may regulate transcriptional factors and modulate gene expression. The nucleus is a mechano-sensor organelle, and sophisticated dynamic mechanoresponsive cytoskeletal and nuclear envelope components support and protect the nucleus, allowing it to perceive and respond to mechano-stimulation. This review speculates on the potential roles of perlecan in the nucleus based on what is already known about nuclear heparan sulphate proteoglycans. Perlecan is frequently found in the nuclei of tumour cells; however, its specific role in these diseased tissues is largely unknown. The aim of this review is to highlight probable roles for this intriguing interactive regulatory proteoglycan in the nucleus of normal and malignant cell types.

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Methanobactin from Methylocystis sp. Strain SB2 Affects Gene Expression and Methane Monooxygenase Activity in Methylosinus trichosporium OB3b

Applied and Environmental Microbiology ◽

10.1128/aem.03981-14 ◽

2015 ◽

Vol 81 (7) ◽

pp. 2466-2473 ◽

Cited By ~ 11

Author(s):

Muhammad Farhan Ul-Haque ◽

Bhagyalakshmi Kalidass ◽

Alexey Vorobev ◽

Bipin S. Baral ◽

Alan A. DiSpirito ◽

...

Keyword(s):

Gene Expression ◽

Methane Monooxygenase ◽

Particulate Methane Monooxygenase ◽

Methylosinus Trichosporium Ob3b ◽

Methylosinus Trichosporium ◽

Monooxygenase Activity ◽

Content Type ◽

Soluble Methane Monooxygenase ◽

A Subunit ◽

Membrane Bound

ABSTRACTMethanotrophs can express a cytoplasmic (soluble) methane monooxygenase (sMMO) or membrane-bound (particulate) methane monooxygenase (pMMO). Expression of these MMOs is strongly regulated by the availability of copper. Many methanotrophs have been found to synthesize a novel compound, methanobactin (Mb), that is responsible for the uptake of copper, and methanobactin produced byMethylosinus trichosporiumOB3b plays a key role in controlling expression of MMO genes in this strain. As all known forms of methanobactin are structurally similar, it was hypothesized that methanobactin from one methanotroph may alter gene expression in another. WhenMethylosinus trichosporiumOB3b was grown in the presence of 1 μM CuCl2, expression ofmmoX, encoding a subunit of the hydroxylase component of sMMO, was very low.mmoXexpression increased, however, when methanobactin fromMethylocystissp. strain SB2 (SB2-Mb) was added, as did whole-cell sMMO activity, but there was no significant change in the amount of copper associated withM. trichosporiumOB3b. IfM. trichosporiumOB3b was grown in the absence of CuCl2, themmoXexpression level was high but decreased by several orders of magnitude if copper prebound to SB2-Mb (Cu-SB2-Mb) was added, and biomass-associated copper was increased. Exposure ofMethylosinus trichosporiumOB3b to SB2-Mb had no effect on expression ofmbnA, encoding the polypeptide precursor of methanobactin in either the presence or absence of CuCl2.mbnAexpression, however, was reduced when Cu-SB2-Mb was added in both the absence and presence of CuCl2. These data suggest that methanobactin acts as a general signaling molecule in methanotrophs and that methanobactin “piracy” may be commonplace.

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Long-Distance Control of Origin Choice and Replication Timing in the Human β-Globin Locus Are Independent of the Locus Control Region

Molecular and Cellular Biology ◽

10.1128/mcb.20.15.5581-5591.2000 ◽

2000 ◽

Vol 20 (15) ◽

pp. 5581-5591 ◽

Cited By ~ 75

Author(s):

Daniel M. Cimbora ◽

Dirk Schübeler ◽

Andreas Reik ◽

Joan Hamilton ◽

Claire Francastel ◽

...

Keyword(s):

Gene Expression ◽

Control Region ◽

Globin Gene ◽

Replication Timing ◽

S Phase ◽

Chromatin Conformation ◽

Erythroid Cells ◽

Long Distance ◽

Targeted Deletion ◽

Globin Gene Expression

ABSTRACT DNA replication in the human β-globin locus is subject to long-distance regulation. In murine and human erythroid cells, the human locus replicates in early S phase from a bidirectional origin located near the β-globin gene. This Hispanic thalassemia deletion removes regulatory sequences located over 52 kb from the origin, resulting in replication of the locus from a different origin, a shift in replication timing to late S phase, adoption of a closed chromatin conformation, and silencing of globin gene expression in murine erythroid cells. The sequences deleted include nuclease-hypersensitive sites 2 to 5 (5′HS2-5) of the locus control region (LCR) plus an additional 27-kb upstream region. We tested a targeted deletion of 5′HS2-5 in the normal chromosomal context of the human β-globin locus to determine the role of these elements in replication origin choice and replication timing. We demonstrate that the 5′HS2-5-deleted locus initiates replication at the appropriate origin and with normal timing in murine erythroid cells, and therefore we conclude that 5′HS2-5 in the classically defined LCR do not control replication in the human β-globin locus. Recent studies also show that targeted deletion of 5′HS2-5 results in a locus that lacks globin gene expression yet retains an open chromatin conformation. Thus, the replication timing of the locus is closely correlated with nuclease sensitivity but not globin gene expression.

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