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Cytomegalovirus (CMV) gene expression is repressed in latency due to heterochromatinization of viral genomes. In murine CMV (MCMV) latently infected mice, viral genomes are bound to histones with heterochromatic modifications, to enzymes that mediate these modifications, and to adaptor proteins that may recruit co-repressor complexes. Kinetic analyses of repressor binding show that these repressors are recruited at the earliest time of infection, suggesting that latency may be the default state. Kidney transplantation leads to epigenetic reprogramming of latent viral chromatin and reactivation of immediate early gene expression. Inflammatory signaling pathways, which activate transcription factors that regulate the major immediate early promoter (MIEP), likely mediate the switch in viral chromatin. [ABSTRACT FROM AUTHOR]

Our previous studies showed that establishment of murine cytomegalovirus (MCMV) latency in vivo is associated with repression of immediate-early gene expression, deacetylation of histones bound to the major immediate-early promoter (MIEP), changes in patterns of methylation of histones, and recruitment of cellular repressors of transcription to the MIEP. Here, we have quantitatively analyzed the kinetics of changes in viral RNA expression, DNA copy number, and recruitment of repressors and activators of transcription to viral promoters during the course of infection. Our results show that changes in viral gene expression correlate with changes in recruitment of RNA polymerase and acetylated histones to viral promoters. Binding of the transcriptional repressors histone deacetylase type 2 (HDAC2), HDAC3, YY1, CBF-1/RBP-Jk, Daxx, and CIR to the MIEP and HDACs to other promoters showed a biphasic pattern: some binding was detectable prior to activation of viral gene expression, then decreased with the onset of transcription and increased again as repression of viral gene expression occurred. Potential binding sites for CBF-1/RBP-Jk and YY1 in the MIEP and for YY1 in the M100 promoter (M100P) were identified by in silico analysis. While recruitment of HDACs was not promoter specific, binding of CBF-1/RBP-Jk and YY1 was restricted to promoters with their cognate sites. Our results suggest that sequences within viral promoters may contribute to establishment of latency through recruitment of transcriptional repressors to these genes. The observation that repressors are bound to the MIEP and other promoters immediately upon infection suggests that latency may be established in some cells very early in infection. [ABSTRACT FROM AUTHOR]

The molecular mechanisms underlying activity-dependent neural circuit growth and plasticity during early brain development remain poorly understood. Protein kinase Mζ (PKMz), an endogenous constitutively active kinase associated with late-phase long-term synaptic potentiation and memory in the mature brain, is expressed in the embryonic Xenopus retinotectal system with heightened levels during peak periods of dendrite growth and synaptogenesis. In vivo rapid time-lapse imaging of actively growing tectal neurons and comprehensive three-dimensional tracking of dynamic dendritic growth behavior finds that altered PKMz activity affects morphologic stabilization. Exogenous expression of PKMz within single neurons stabilizes dendritic filopodia by increasing dendritic filopodial lifetimes and decreasing filopodial additions, eliminations, and motility, whereas long-term in vivo imaging demonstrates restricted expansion of the dendritic arbor. Alternatively, blocking endogenous PKMz activity in individual growing tectal neurons with an inhibitory peptide (ζ-inhibitory peptide) destabilizes dendritic filopodia and over long periods promotes excessive arbor expansion. Furthermore, inhibiting endogenous PKMz throughout the tectum decreases colocalization of immunostained presynaptic and postsynaptic markers, SNAP-25 and PSD-95, respectively, suggesting impaired synapse maintenance. Together, these results implicate PKMz activity in restricting dendritic arborization during embryonic brain circuit development through synaptotropic stabilization of dynamic processes. [ABSTRACT FROM AUTHOR]

It is well documented that unliganded thyroid hormone receptor (TR) functions as a transcriptional repressor of specific cellular target genes by acting in concert with a corepressor complex harboring histone deacetylase (HDAC) activity. To fully explore the cofactors that interact with the transcriptionally repressive form of TR, we biochemically isolated a multiprotein complex that assembles on a TR-retinoid X receptor (RXR) heterodimer in HeLa nuclear extracts and identified its polypeptide components by mass spectrometry. A subset of TR-RXR-associated polypeptides included NCoR, SMRT, TBL1, and HDAC3, which represent the core components of a previously described NCoR/SMRT corepressor complex. We also identified several polypeptides that constitute a DNA-dependent protein kinase (DNA-PK) enzyme complex, a regulator of DNA repair, recombination, and transcription. These polypeptides included the catalytic subunit DNA-PKcs, the regulatory subunits Ku70 and Ku86, and the poly(ADP-ribose) polymerase 1. Density gradient fractionation and immunoprecipitation analyses provided evidence for the existence of a high molecular weight TR-RXR-corepressor holocomplex containing both NCoR/SMRT and DNA-PK complexes. Chromatin immunoprecipitation studies confirmed that unliganded TR-RXR recruits both complexes to the triiodothyronine-responsive region of growth hormone gene in vivo. Interestingly, DNA-PKcs, a member of the phosphatidylinositol 3-kinase family, was found to phosphorylate HDAC3 when the purified TR-RXR-corepressor holocomplex was incubated with ATP. This phosphorylation was accompanied by a significant enhancement of the HDAC activity of this complex. Collectively, our results indicated that DNA-PK promotes the establishment of a repressive chromatin at a TR target promoter by enhancing the HDAC activity of the receptor-bound NCoR/SMRT corepressor complex. [ABSTRACT FROM AUTHOR]

Spectral imaging is an important tool for a wide variety of applications. We present a technique for spectral imaging using computational imaging pattern based on compressive sensing (CS). The spectral and spatial information is simultaneously obtained using a fiber spectrometer and the spatial light modulation without mechanical scanning. The method allows high-speed, stable, and sub sampling acquisition of spectral data from specimens. The relationship between sampling rate and image quality is discussed and two CS algorithms are compared. [ABSTRACT FROM AUTHOR]

We demonstrate that, by undersampling scanning object with a reconstruction algorithm related to compressed sensing, an image with the resolution exceeding the finest resolution defined by the numerical aperture of the system can be obtained. Experimental results show that the measurements needed to achieve sub-Rayleigh resolution enhancement can be less than 10% of the pixels of the object. This method offers a general approach applicable to point-by-point illumination super-resolution techniques. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (CMV) is a ubiquitous herpesvirus with the ability to establish a lifelong latent infection. The mechanism by which this occurs is not well understood. Regulation of, for example, immediate-early (IE) gene expression is thought to be a critical control point in transcriptional control of the switch between latency and reactivation. Here, we present evidence that supports previous studies showing that the majority of genomes are quiescent with respect to gene expression. To study the possible role of epigenetic factors that may be involved in repression of ie gene expression in latency, we have analyzed changes in the patterns of modifications of histones bound to the major IE promoter (MIEP) in the kidneys of acutely and latently infected mice. Our studies show that, like herpes simplex virus, murine CMV genomes become relatively enriched in histones in latent infection. There are dramatic changes in modifications of histones associated with the MIEP when latency is established: H3 and H4 become hypoacetylated and H3 is hypomethylated at lysine 4, while H3 lysine 9 is hypermethylated in latently infected mice. These changes are accompanied by a relative loss of RNA polymerase and gain of heterochromatin protein 1 γ and Yin-Yang 1 bound to the MIEP. Our studies suggest that, in the majority of cells, CMV establishes a true latent infection, defined as the lack of expression of genes associated with productive infection, and that this occurs through changes in histone modifications and recruitment of transcriptional silencing factors to the MIEP. [ABSTRACT FROM AUTHOR]

The title compound, C22H16O2, was prepared from anthrone and 3-methoxy­benzaldehyde in the presence of pyridine. X-ray analysis shows that the anthraquinone ring system is not planar. The central six-membered ring adopts an asymmetric boat conformation, in which the carbonyl C and the para-C atoms deviate from the plane of the other four atoms by 0.162 (8) and 0.267 (8) Å, respectively. Inter­molecular C—H⋯O hydrogen bonds are present in the crystal structure. [ABSTRACT FROM AUTHOR]

Objective: To study the effects of butylphthalide on bronchial asthma in guinea pigs, and investigate the involvement of endothelin., Methods: In guinea pigs, bronchial asthma was induced by injection of ovalbumin (OVA) and provoked by inhalation of OVA, and the effects of butylphthalide on asthma were evaluated through the changes it induced by OVA, pulmonary function, endothelin-1 (ET-1) contents and activity of endothelin converting enzyme-1 (ECE-1) in bronchoalveolar lavage fluid (BALF), serum and lung tissue, and the gene expression of ET-1 in lung tissue., Results: Butylphthalide significantly improved pulmonary function, lowered asthmatic behavior score, inhibited the activity of ECE-1, and reduced ET-1 gene expression level in lung tissue., Conclusions: Butylphthalide has an anti-asthma effect and the mechanisms involve inhibition of ECE-1 activity and lowering of ET-1geng expression.

Objective: To explore the biological function of rhoptry protein 38 (ROP38) of Toxoplasma gondii , and to identify the reactogenicity of the recombinant protein (rROP38)., Methods: The ROP38 was amplified by RT-PCR from T. gondii RH strain, and was cloned into prokaryotic expression vector pET-28a (+). The recombinant plasmid was transformed into E. coli BL21 (DE3) competent cells. Then the rROP38 was analyzed by SDS-PAGE and identified by Western blot., Results: SDS-PAGE showed that rROP38 was efficient expression with a molecular weight of about 43 kD. Western blot showed that rROP38 reacted with antibody of His tag or human positive antibody, which indicated that ROP38 had good reactogenicity and could be a serological diagnostic antigen., Conclusions: The study successfully obtains the rROP38 of T. gondii with good reactogenicity.