2,877 research outputs found
Towards the Post-Secular City? London since the 1960s
It is possible to interpret the available statistical evidence to argue that — when the presence of minority traditions is taken into account — the level of religious prac-tice in London in the early twenty-first century was quite similar to that in the early twentieth century. London may be exceptional in some respects, but it is nevertheless indicative of wider patterns of religious change over the last half-century,which have hitherto received little academic attention. The London case reveals a dynamic picture of simultaneous decline and resurgence, with overall rapid growth in Pentecostalism, Hinduism, Islam, and Sikhism while traditional Christian denominations have generally been contracting. However, the Christian picture is further variegated at the local level, with significant pockets of growth even in the historic churches, notably but not only in the Church of England Diocese of Lon-don. Moreover, the wider social engagements of many religious groups have given them an impact beyond their actual membership
Unwrapping of DNA-protein complexes under external stretching
A DNA-protein complex modelled by a semiflexible chain and an attractive
spherical core is studied in the situation when an external stretching force is
acting on one end monomer of the chain while the other end monomer is kept
fixed in space. Without stretching force, the chain is wrapped around the core.
By applying an external stretching force, unwrapping of the complex is induced.
We study the statics and the dynamics of the unwrapping process by computer
simulation and simple phenomenological theory. We find two different scenarios
depending on the chain stiffness: For a flexible chain, the extension of the
complex scales linearly with the external force applied. The sphere-chain
complex is disordered, i.e. there is no clear winding of the chain around the
sphere. For a stiff chain, on the other hand, the complex structure is ordered,
which is reminiscent to nucleosome. There is a clear winding number and the
unwrapping process under external stretching is discontinuous with jumps of the
distance-force curve. This is associated to discrete unwinding processes of the
complex. Our predictions are of relevance for experiments, which measure
force-extension curves of DNA-protein complexes, such as nucleosome, using
optical tweezers.Comment: 8 pages, 7 figure
All-or-none switching of transcriptional activity on single DNA molecules caused by a discrete conformational transition
Recently, it has been confirmed that long duplex DNA molecules with sizes
larger than several tens of kilo-base pairs (kbp), exhibit a discrete
conformational transition from an elongated coil state to a compact globule
state upon the addition of various kinds of chemical species that usually
induce DNA condensation. In this study, we performed a single-molecule
observation on a large DNA, Lambda ZAP II DNA (ca. 41 kbp), in a solution
containing RNA polymerase and substrates along with spermine, a tetravalent
cation, at different concentrations, by use of fluorescence staining of both
DNA and RNA. We found that transcription, or RNA production, is completely
inhibited in the compact state, but is actively performed in the unfolded coil
state. Such an all-or-none effect on transcriptional activity induced by the
discrete conformational transition of single DNA molecules is discussed in
relation to the mechanism of the regulation of large-scale genetic activity.Comment: 14 pages, 2 figure
Orientational correlations in confined DNA
We study how the orientational correlations of DNA confined to nanochannels
depend on the channel diameter D by means of Monte Carlo simulations and a
mean-field theory. This theory describes DNA conformations in the
experimentally relevant regime where the Flory-de Gennes theory does not apply.
We show how local correlations determine the dependence of the end-to-end
distance of the DNA molecule upon D. Tapered nanochannels provide the necessary
resolution in D to study experimentally how the extension of confined DNA
molecules depends upon D. Our experimental and theoretical results are in
qualitative agreement.Comment: Revised version including supplemental material, 7 pages, 8 figure
The formin FHOD1 and the small GTPase Rac1 promote vaccinia virus actin-based motility
Vaccinia virus dissemination relies on the N-WASP– ARP2/3 pathway, which mediates actin tail formation underneath cell-associated extracellular viruses (CEVs). Here, we uncover a previously unappreciated role for the formin FHOD1 and the small GTPase Rac1 in vaccinia actin tail formation. FHOD1 depletion decreased the number of CEVs forming actin tails and impaired the elongation rate of the formed actin tails. Recruitment of FHOD1 to actin tails relied on its GTPase binding domain in addition to its FH2 domain. In agreement with previous studies showing that FHOD1 is activated by the small GTPase Rac1, Rac1 was enriched and activated at the membrane surrounding actin tails. Rac1 depletion or expression of dominant-negative Rac1 phenocopied the effects of FHOD1 depletion and impaired the recruitment of FHOD1 to actin tails. FHOD1 overexpression rescued the actin tail formation defects observed in cells overexpressing dominant-negative Rac1. Altogether, our results indicate that, to display robust actin-based motility, vaccinia virus integrates the activity of the N-WASP– ARP2/3 and Rac1–FHOD1 pathways.Fil: Alvarez, Diego Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Yale. School of Medicine; Estados UnidosFil: Agaisse, Herve. University of Yale. School of Medicine; Estados Unido
The mRNA expression of SETD2 in human breast cancer: Correlation with clinico-athological parameters
BACKGROUND: SET domain containing protein 2 (SETD2) is a histone methyltransferase that is involved in transcriptional elongation. There is evidence that SETD2 interacts with p53 and selectively regulates its downstream genes. Therefore, it could be implicated in the process of carcinogenesis. Furthermore, this gene is located on the short arm of chromosome 3p and we previously demonstrated that the 3p21.31 region of chromosome 3 was associated with permanent growth arrest of breast cancer cells. This region includes closely related genes namely: MYL3, CCDC12, KIF9, KLHL18 and SETD2. Based on the biological function of these genes, SETD2 is the most likely gene to play a tumour suppressor role and explain our previous findings. Our objective was to determine, using quantitative PCR, whether the mRNA expression levels of SETD2 were consistent with a tumour suppressive function in breast cancer. This is the first study in the literature to examine the direct relationship between SETD2 and breast cancer. METHODS: A total of 153 samples were analysed. The levels of transcription of SETD2 were determined using quantitative PCR and normalized against (CK19). Transcript levels within breast cancer specimens were compared to normal background tissues and analyzed against conventional pathological parameters and clinical outcome over a 10 year follow-up period. RESULTS: The levels of SETD2 mRNA were significantly lower in malignant samples (p = 0.0345) and decreased with increasing tumour stage. SETD2 expression levels were significantly lower in samples from patients who developed metastasis, local recurrence, or died of breast cancer when compared to those who were disease free for > 10 years (p = 0.041). CONCLUSION: This study demonstrates a compelling trend for SETD2 transcription levels to be lower in cancerous tissues and in patients who developed progressive disease. These findings are consistent with a possible tumour suppressor function of this gene in breast cancer
Epigenetic Regulation of Matrix Metalloproteinase-1 and -3 Expression in Mycobacterium tuberculosis Infection.
In pulmonary tuberculosis (TB), the inflammatory immune response against Mycobacterium tuberculosis (Mtb) is associated with tissue destruction and cavitation, which drives disease transmission, chronic lung disease, and mortality. Matrix metalloproteinase (MMP)-1 is a host enzyme critical for the development of cavitation. MMP expression has been shown to be epigenetically regulated in other inflammatory diseases, but the importance of such mechanisms in Mtb-associated induction of MMP-1 is unknown. We investigated the role of changes in histone acetylation in Mtb-induced MMP expression using inhibitors of histone deacetylases (HDACs) and histone acetyltransferases (HAT), HDAC siRNA, promoter-reporter constructs, and chromatin immunoprecipitation assays. Mtb infection decreased Class I HDAC gene expression by over 50% in primary human monocyte-derived macrophages but not in normal human bronchial epithelial cells (NHBEs). Non-selective inhibition of HDAC activity decreased MMP-1/-3 expression by Mtb-stimulated macrophages and NHBEs, while class I HDAC inhibition increased MMP-1 secretion by Mtb-stimulated NHBEs. MMP-3 expression, but not MMP-1, was downregulated by siRNA silencing of HDAC1. Inhibition of HAT activity also significantly decreased MMP-1/-3 secretion by Mtb-infected macrophages. The MMP-1 promoter region between -2,001 and -2,942 base pairs from the transcriptional start site was key in control of Mtb-driven MMP-1 gene expression. Histone H3 and H4 acetylation and RNA Pol II binding in the MMP-1 promoter region were increased in stimulated NHBEs. In summary, epigenetic modification of histone acetylation via HDAC and HAT activity has a key regulatory role in Mtb-dependent gene expression and secretion of MMP-1 and -3, enzymes which drive human immunopathology. Manipulation of epigenetic regulatory mechanisms may have potential as a host-directed therapy to improve outcomes in the era of rising TB drug resistance
Quantitative analysis of chromatin compaction in living cells using FLIM-FRET
FRET analysis of cell lines expressing fluorescently tagged histones on separate nucleosomes demonstrates that variations in chromosome compaction occur during mitosis
Fashioning the Flapper: Clothing as a Catalyst for Social Change in 1920s America
Fashion has been a catalyst for social change throughout human history. Fashion in 1920s America in particular reflects society\u27s rapidly evolving attitudes towards gender and race. Beginning with how corsetry heavily restricted women for nearly four hundred years up until the twentieth century, this thesis explores how clothing has acted as a tool for societal progression following World War I and Women\u27s Suffrage and during the Jazz Age and The Harlem Renaissance. Specifically, this thesis examines how the influence of jazz music and dance that originated from Black American communities led to the creation of the flapper evening dress. The impact of the rise and fall of corsetry, the infamous flapper, and Black culture has shaped fashion throughout this highly influential decade and in turn, these fashions helped shape society
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