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  • A CD8+ T cell immune evasion protein specific to Epstein-Barr virus and its close relatives in Old World primates. 17620360

    gamma 1-Herpesviruses such as Epstein-Barr virus (EBV) have a unique ability to amplify virus loads in vivo through latent growth-transforming infection. Whether they, like alpha- and beta-herpesviruses, have been driven to actively evade immune detection of replicative (lytic) infection remains a moot point. We were prompted to readdress this question by recent work (Pudney, V.A., A.M. Leese, A.B. Rickinson, and A.D. Hislop. 2005. J. Exp. Med. 201:349-360; Ressing, M.E., S.E. Keating, D. van Leeuwen, D. Koppers-Lalic, I.Y. Pappworth, E.J.H.J. Wiertz, and M. Rowe. 2005. J. Immunol. 174:6829-6838) showing that, as EBV-infected cells move through the lytic cycle, their susceptibility to EBV-specific CD8(+) T cell recognition falls dramatically, concomitant with a reductions in transporter associated with antigen processing (TAP) function and surface human histocompatibility leukocyte antigen (HLA) class I expression. Screening of genes that are unique to EBV and closely related gamma 1-herpesviruses of Old World primates identified an early EBV lytic cycle gene, BNLF2a, which efficiently blocks antigen-specific CD8(+) T cell recognition through HLA-A-, HLA-B-, and HLA-C-restricting alleles when expressed in target cells in vitro. The small (60-amino acid) BNLF2a protein mediated its effects through interacting with the TAP complex and inhibiting both its peptide- and ATP-binding functions. Furthermore, this targeting of the major histocompatibility complex class I pathway appears to be conserved among the BNLF2a homologues of Old World primate gamma 1-herpesviruses. Thus, even the acquisition of latent cycle genes endowing unique growth-transforming ability has not liberated these agents from evolutionary pressure to evade CD8(+) T cell control over virus replicative foci.
    Document Type:
    Reference
    Product Catalog Number:
    MABF249
    Product Catalog Name:
    Anti-Tapasin Antibody, clone 7F6
  • The cell adhesion molecule L1 regulates the expression of choline acetyltransferase and the development of septal cholinergic neurons. 22399087

    Mutations in the L1 gene cause severe brain malformations and mental retardation. We investigated the potential roles of L1 in the regulation of choline acetyltransferase (ChAT) and in the development of septal cholinergic neurons, which are known to project to the hippocampus and play key roles in cognitive functions. Using stereological approaches, we detected significantly fewer ChAT-positive cholinergic neurons in the medial septum and vertical limb of the diagonal band of Broca (MS/VDB) of 2-week-old L1-deficient mice compared to wild-type littermates (1644 ± 137 vs. 2051 ± 165, P = 0.038). ChAT protein levels in the septum were 53% lower in 2-week-old L1-deficient mice compared to wild-type littermates. ChAT activity in the septum was significantly reduced in L1-deficient mice compared to wild-type littermates at 1 (34%) and 2 (40%) weeks of age. In vitro, increasing doses of L1-Fc induced ChAT activity in septal neurons with a significant linear trend (*P = 0.0065). At 4 weeks of age in the septum and at all time points investigated in the caudate-putamen (CPu), the number of ChAT-positive neurons and the levels of ChAT activity were not statistically different between L1-deficient mice and wild-type littermates. The total number of cells positive for the neuronal nuclear antigen (NeuN) in the MS/VDB and CPu was not statistically different in L1-deficient mice compared to wild-type littermates, and comparable expression of the cell cycle marker Ki67 was observed. Our results indicate that L1 is required for the timely maturation of septal cholinergic neurons and that L1 promotes the expression and activity of ChAT in septal neurons.
    Document Type:
    Reference
    Product Catalog Number:
    AB144P
    Product Catalog Name:
    Anti-Choline Acetyltransferase Antibody
  • Cell cycle- and cancer-associated gene networks activated by Dsg2: evidence of cystatin a deregulation and a potential role in cell-cell adhesion. 25785582

    Cell-cell adhesion is paramount in providing and maintaining multicellular structure and signal transmission between cells. In the skin, disruption to desmosomal regulated intercellular connectivity may lead to disorders of keratinization and hyperproliferative disease including cancer. Recently we showed transgenic mice overexpressing desmoglein 2 (Dsg2) in the epidermis develop hyperplasia. Following microarray and gene network analysis, we demonstrate that Dsg2 caused a profound change in the transcriptome of keratinocytes in vivo and altered a number of genes important in epithelial dysplasia including: calcium-binding proteins (S100A8 and S100A9), members of the cyclin protein family, and the cysteine protease inhibitor cystatin A (CSTA). CSTA is deregulated in several skin cancers, including squamous cell carcinomas (SCC) and loss of function mutations lead to recessive skin fragility disorders. The microarray results were confirmed by qPCR, immunoblotting, and immunohistochemistry. CSTA was detected at high level throughout the newborn mouse epidermis but dramatically decreased with development and was detected predominantly in the differentiated layers. In human keratinocytes, knockdown of Dsg2 by siRNA or shRNA reduced CSTA expression. Furthermore, siRNA knockdown of CSTA resulted in cytoplasmic localization of Dsg2, perturbed cytokeratin 14 staining and reduced levels of desmoplakin in response to mechanical stretching. Both knockdown of either Dsg2 or CSTA induced loss of cell adhesion in a dispase-based assay and the effect was synergistic. Our findings here offer a novel pathway of CSTA regulation involving Dsg2 and a potential crosstalk between Dsg2 and CSTA that modulates cell adhesion. These results further support the recent human genetic findings that loss of function mutations in the CSTA gene result in skin fragility due to impaired cell-cell adhesion: autosomal-recessive exfoliative ichthyosis or acral peeling skin syndrome.
    Document Type:
    Reference
    Product Catalog Number:
    AB4065
  • Cell cycle regulation of the murine 8-oxoguanine DNA glycosylase (mOGG1): mOGG1 associates with microtubules during interphase and mitosis. 15474421

    8-Oxoguanine DNA glycosylase (OGG1) is a major DNA repair enzyme in mammalian cells. OGG1 participates in the repair of 8-oxoG, the most abundant known DNA lesion induced by endogenous reactive oxygen species in aerobic organisms. In this study, antibodies directed against purified recombinant human OGG1 (hOGG1) or murine (mOGG1) protein were chemically conjugated to either the photosensitizer Rose Bengal or the fluorescent dye Texas red. These dye-protein conjugates, in combination with binding assays, were used to identify associations between mOGG1 and the cytoskeleton of NIH3T3 fibroblasts. Results from these binding studies showed that mOGG1 associates with the cytoskeleton by specifically binding to the centriole and microtubules radiating from the centrosome at interphase and the spindle assembly at mitosis. Similar results were obtained with hOGG1. Together results reported in this study suggest that OGG1 is a microtubule-associated protein itself or that OGG1 utilizes yet to be identified motor proteins to ride on microtubules as tracks facilitating the movement and redistribution of cytoplasmic OGG1 pools during interphase and mitosis and in response to oxidative DNA damage.
    Document Type:
    Reference
    Product Catalog Number:
    MAB1636
  • Cell division: control of the chromosomal passenger complex in time and space. 24091645

    The ultimate goal of cell division is equal transmission of the duplicated genome to two new daughter cells. Multiple surveillance systems exist that monitor proper execution of the cell division program and as such ensure stability of our genome. One widely studied protein complex essential for proper chromosome segregation and execution of cytoplasmic division (cytokinesis) is the chromosomal passenger complex (CPC). This highly conserved complex consists of Borealin, Survivin, INCENP, and Aurora B kinase, and has a dynamic localization pattern during mitosis and cytokinesis. Not surprisingly, it also performs various functions during these phases of the cell cycle. In this review, we will give an overview of the latest insights into the regulation of CPC localization and discuss if and how specific localization impacts its diverse functions in the dividing cell.
    Document Type:
    Reference
    Product Catalog Number:
    06-570
    Product Catalog Name:
    Anti-phospho-Histone H3 (Ser10) Antibody, Mitosis Marker
  • Cell cycle arrest at the initiation step of human chromosomal DNA replication causes DNA damage. 15456844

    Cell cycle arrest in response to environmental effects can lead to DNA breaks. We investigated whether inhibition of DNA replication during the initiation step can lead to DNA damage and characterised a cell-cycle-arrest point at the replication initiation step before the establishment of active replication forks. This arrest can be elicited by the iron chelators mimosine, ciclopirox olamine or 2,2'-bipyridyl, and can be reversed by the removal of the drugs or the addition of excess iron. Iron depletion induces DNA double-strand breaks in treated cells, and activates a DNA damage response that results in focal phosphorylation of histone H2AX, focal accumulation of replication protein A (RPA) and ATR (ATM and Rad3-related kinase), and activation of CHK1 kinase. Abrogation of the checkpoint response does not abolish the cell cycle arrest before the establishment of active DNA replication forks. DNA breaks appear concomitantly with the arrival of cells at the arrest point and persist upon release from the cell cycle block. We conclude that DNA double-strand breaks are the consequence, and not the cause, of cell cycle arrest during the initiation step of DNA replication by iron chelation.
    Document Type:
    Reference
    Product Catalog Number:
    07-164
    Product Catalog Name:
    Anti-phospho-H2A.X (Ser139) Antibody
  • Cell cycle-dependent accumulation of histone H3.3 and euchromatic histone modifications in pericentromeric heterochromatin in response to a decrease in DNA methylation le ... 20599948

    In mammals, DNA methylation is an important epigenetic mark that is associated with gene silencing, particularly in constitutive heterochromatin. However, the effect of DNA methylation on other epigenetic properties of chromatin is controversial. In this study, we show that inhibition of DNA methylation in mouse fibroblast cells affects histone modification and the subnuclear localization of histone H3.3 in a cell cycle-dependent manner. Using a DNA methyltransferase (Dnmt) inhibitor 5-aza-2'-deoxycytidine (5-aza-dC), we found that reduced levels of DNA methylation were associated with the activation of transcription from centromeric and pericentromeric satellite repeats. The de-repressed pericentromeric chromatin was enriched in euchromatic histone modifications such as acetylation of histone H4, and di- and tri-methylation of lysine 4 on histone H3. Spatio-temporal analysis showed that the accumulation of these euchromatic histone modifications occurred during the second S phase following 5-aza-dC treatment, corresponding precisely with a shift in replication timing of the pericentromeric satellite repeats from middle/late S phase to early S phase. Moreover, we found that histone H3.3 was deposited on the pericentromeric heterochromatin prior to the accumulation of the euchromatic histone modifications. These results suggest that DNA CpG methylation is essential for the proper organization of pericentromeric heterochromatin in differentiated mouse cells.
    Document Type:
    Reference
    Product Catalog Number:
    07-442
    Product Catalog Name:
    Anti-trimethyl-Histone H3 (Lys9) Antibody
  • Cell cycle-dependent turnover of 5-hydroxymethyl cytosine in mouse embryonic stem cells. 24340069

    Hydroxymethylcytosine in the genome is reported to be an intermediate of demethylation. In the present study, we demonstrated that maintenance methyltransferase Dnmt1 scarcely catalyzed hemi-hydroxymethylated DNA and that the hemi-hydroxymethylated DNA was not selectively recognized by the SRA domain of Uhrf1, indicating that hydroxymethylcytosine is diluted in a replication-dependent manner. A high level of 5-hydroxymethylcytosine in mouse embryonic stem cells was produced from the methylcytosine supplied mainly by de novo-type DNA methyltransferases Dnmt3a and Dnmt3b. The promoter regions of the HoxA gene cluster showed a high hydroxymethylation level whilst the methylcytosine level was quite low, suggesting that methylated CpG is actively hydroxylated during proliferation. All the results indicate that removal and production of hydroxymethylcytosine are regulated in replication-dependent manners in mouse embryonic stem cells.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Cell cycle, oncogenic and tumor suppressor pathways regulate numerous long and macro non-protein-coding RNAs. 24594072

    The genome is pervasively transcribed but most transcripts do not code for proteins, constituting non-protein-coding RNAs. Despite increasing numbers of functional reports of individual long non-coding RNAs (lncRNAs), assessing the extent of functionality among the non-coding transcriptional output of mammalian cells remains intricate. In the protein-coding world, transcripts differentially expressed in the context of processes essential for the survival of multicellular organisms have been instrumental in the discovery of functionally relevant proteins and their deregulation is frequently associated with diseases. We therefore systematically identified lncRNAs expressed differentially in response to oncologically relevant processes and cell-cycle, p53 and STAT3 pathways, using tiling arrays.We found that up to 80% of the pathway-triggered transcriptional responses are non-coding. Among these we identified very large macroRNAs with pathway-specific expression patterns and demonstrated that these are likely continuous transcripts. MacroRNAs contain elements conserved in mammals and sauropsids, which in part exhibit conserved RNA secondary structure. Comparing evolutionary rates of a macroRNA to adjacent protein-coding genes suggests a local action of the transcript. Finally, in different grades of astrocytoma, a tumor disease unrelated to the initially used cell lines, macroRNAs are differentially expressed.It has been shown previously that the majority of expressed non-ribosomal transcripts are non-coding. We now conclude that differential expression triggered by signaling pathways gives rise to a similar abundance of non-coding content. It is thus unlikely that the prevalence of non-coding transcripts in the cell is a trivial consequence of leaky or random transcription events.
    Document Type:
    Reference
    Product Catalog Number:
    12-370
    Product Catalog Name:
    Normal Rabbit IgG
  • Targeting L1 cell adhesion molecule expression using liposome-encapsulated siRNA suppresses prostate cancer bone metastasis and growth. 25294816

    The L1 cell adhesion molecule (L1CAM) has been implicated in tumor progression of many types of cancers, but its role in prostate cancer and its application in targeted gene therapy have not been investigated. Herein, we demonstrated that the L1CAM was expressed in androgen-insensitive and highly metastatic human prostate cancer cell lines. The correlation between L1CAM expression and prostate cancer metastasis was also validated in serum samples of prostate cancer patients. Knockdown of L1CAM expression in prostate cancer cells by RNA interference significantly decreased their aggressive behaviors, including colony formation, migration and invasion in vitro, and tumor formation in a metastatic murine model. These anti-malignant phenotypes of L1CAM-knockdown cancer cells were accompanied by G0/G1 cell cycle arrest and suppression of matrix metalloproteinase (MMP)-2 and MMP-9 expression and nuclear factor NF-κB activation. In vivo targeting of L1CAM expression using liposome-encapsulated L1CAM siRNAs effectively inhibited prostate cancer growth in mouse bone, which was associated with decreased L1CAM expression and cell proliferation by tumor cells. These results provide the first evidence for L1CAM being a major contributor to prostate cancer metastasis and translational application of siRNA-based L1CAM-targeted therapy.
    Document Type:
    Reference
    Product Catalog Number:
    AB19016
    Product Catalog Name:
    Anti-MMP-9 Antibody, Catalytic domain