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  • Genome-wide ChIP-seq analysis of TCF4 binding regions in colorectal cancer cells. 25550940

    TCF4 (transcriptional factor 4) forms a complex with its transcriptional coactivator β-catenin and the coactivator carries the final signal output from the canonical Wnt signaling pathway, which is essential for the growth of normal epithelium and also plays important roles in carcinogenesis of colon epithelium. We aimed to gain a better understanding of the genes bound by TCF4 in colorectal cancer cells.SW620 human colorectal cancer cells were cultured. The TCF4 antibody of this study was confirmed in SW620 cells by Western Blot. A ChIP-seq based genome-wide analysis of TCF4 chromatin occupancy in colorectal cancer cells was conducted and 1506 high confidence TCF4 binding sites wereidentified.Sequence analysis revealed that the binding sites harbor a consensus sequence of C-G/C-A-G-C-T/C-C-T-T-C. Gene ontology and pathway analysis showed that TCF4 regulated 18 genes in Wnt signaling pathway and 97 other transcription factors.Our results suggest TCF4 binding regions were enriched with a motif of C-G/C-A-G-C-T/C-C-T-T-C. The gene regulation of TCF4 may be conserved in colorectal cancer and glioma cells. TCF4 may be involved in a series of important biological processes such as regulation of metabolic and biosynthetic (GO: 0010604, GO: 0031328, GO: 0009891, GO: 0051173, GO: 0010557, GO: 0045935), adhesion (GO: 0007155, GO: 0022610), apoptosis (GO: 0042981, GO: 0043067, GO: 0010941), and important signaling pathways (Wnt, Chemokine, Calciu, GnRH).
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    05-511
    Produktbezeichnung:
    Anti-TCF-4 Antibody, clone 6H5-3

  • A calcium-induced calcium release mechanism supports luteinizing hormone-induced testosterone secretion in mouse Leydig cells. 20519450

    Leydig cells are responsible for the synthesis and secretion of testosterone, processes controlled by luteinizing hormone (LH). Binding of LH to a G protein-coupled receptor in the plasma membrane results in an increase in cAMP and in intracellular Ca(2+) concentration ([Ca(2+)](i)). Here we show, using immunofluorescence, that Leydig cells express ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP(3)Rs). Measurements of intracellular calcium changes using the fluorescent calcium-sensitive dye fluo-3 and confocal microscopy show that both types of receptors are involved in a calcium-induced calcium release (CICR) mechanism, which amplifies the initial Ca(2+) influx through plasma membrane T-type calcium channels (Ca(V)3). The RyRs and IP(3)Rs are functional, as judged from both their activation by caffeine and IP(3) and block by ryanodine and 2-aminoethoxydiphenyl borate (2-APB), respectively. RyRs are the principal players involved in the release of Ca(2+) from the endoplasmic reticulum, as evidenced by the fact that global Ca(2+) changes evoked by LH are readily blocked by 100 muM ryanodine but not by 2-APB or xestospongin C. Finally, steroid production by Leydig cells is inhibited by ryanodine but not by 2-APB. These results not only broaden our understanding of the role played by calcium in Leydig cells but also show, for the first time, that RyRs have an important role in determining testosterone secretion by the testis.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    Mehrere
    Produktbezeichnung:
    Mehrere

  • Calcium/calmodulin-dependent protein kinase II and calmodulin: regulators of the meiotic spindle in mouse eggs. 9882483

    Elevation of intracellular free calcium causes egg activation by initiating a cascade of interacting signaling pathways that, in unison, act to remodel the cytoplasmic compartment and the nuclear compartment of the egg. We show here that calcium/calmodulin-dependent protein kinase II (CaM kinase II) is tightly associated with the meiotic spindle and that 5 min after egg activation there is a transient, tight association of calmodulin (colocalized with CaM kinase II) on the meiotic spindle. These correlative observations caused us to test whether activation of CaM kinase II mediated the chromosomal transit into an anaphase configuration. We demonstrate that calcium and calmodulin, at physiological levels, along with ATP were capable of driving the spindle (with its associated CaM kinase II) into an anaphase configuration in a permeabilized egg system. The transit into anaphase was dependent on the presence of both calcium and calmodulin and occurred normally when they were present at a ratio of 4 to 1. Peptide and pharmacologic inhibitors of CaM kinase II blocked the transit into anaphase, both in the permeabilized egg system and in living eggs (inhibitors of protein kinase C did not block the transit into anaphase). Using a biochemical approach we confirm that CaM kinase II increases in activity 5 min after egg activation and that a second increase occurs 45 min after activation at the approximate time that the contractile ring of the second polar body is constricting. This corresponds to the approximate time when calmodulin and CaM kinase II colocalize at several points in the activated egg including the region containing midzone microtubules. CaM kinase II appears localized on midzone microtubules as soon as they form and may have a role in specifying the position of the contractile ring of the second polar body.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    05-173
    Produktbezeichnung:
    Anti-Calmodulin Antibody

  • Calcium entry and α-synuclein inclusions elevate dendritic mitochondrial oxidant stress in dopaminergic neurons. 23761910

    The core motor symptoms of Parkinson's disease (PD) are attributable to the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc). Mitochondrial oxidant stress is widely viewed a major factor in PD pathogenesis. Previous work has shown that activity-dependent calcium entry through L-type channels elevates perinuclear mitochondrial oxidant stress in SNc dopaminergic neurons, providing a potential basis for their selective vulnerability. What is less clear is whether this physiological stress is present in dendrites and if Lewy bodies, the major neuropathological lesion found in PD brains, exacerbate it. To pursue these questions, mesencephalic dopaminergic neurons derived from C57BL/6 transgenic mice were studied in primary cultures, allowing for visualization of soma and dendrites simultaneously. Many of the key features of in vivo adult dopaminergic neurons were recapitulated in vitro. Activity-dependent calcium entry through L-type channels increased mitochondrial oxidant stress in dendrites. This stress progressively increased with distance from the soma. Examination of SNc dopaminergic neurons ex vivo in brain slices verified this pattern. Moreover, the formation of intracellular α-synuclein Lewy-body-like aggregates increased mitochondrial oxidant stress in perinuclear and dendritic compartments. This stress appeared to be extramitochondrial in origin, because scavengers of cytosolic reactive oxygen species or inhibition of NADPH oxidase attenuated it. These results show that physiological and proteostatic stress can be additive in the soma and dendrites of vulnerable dopaminergic neurons, providing new insight into the factors underlying PD pathogenesis.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    Mehrere
    Produktbezeichnung:
    Mehrere

  • Calcium hydroxide regulates bone sialoprotein gene transcription in human osteoblast-like Saos2 cells. 21467818

    Bone sialoprotein (BSP) is a mineralized tissue-specific protein expressed in differentiated osteoblasts that appears to function in the initial mineralization of bone. Calcium hydroxide (Ca(OH)(2)) is a basic salt that has been widely used for a variety of applications in dentistry, due to its antimicrobial effects and its capability of inducing hard tissue formation. However, details of the mechanism involved in the mineralization induced by Ca(OH)(2) are still unclear. In the present study, Ca(OH)(2) (0.4 mM) was found to increase the levels of BSP and Runx2 mRNA at 3 h in human osteoblast-like Saos2 cells. Transient transfection assays were performed using chimeric constructs of the human BSP gene promoter linked to a luciferase reporter gene. Treatment of Saos2 cells with Ca(OH)(2) (0.4 mM) increased the luciferase activities of the constructs between -60LUC and -927LUC at 12 h. Gel shift analysis showed that Ca(OH)(2) (0.4 mM) increased the binding of nuclear protein to CRE1, CRE2 and FRE. Antibodies against CREB1, c-Fos, c-Jun, JunD, Fra2 and P300 disrupted the formation of the CRE1- and CRE2-protein complexes, and antibodies against Dlx5, Msx2, Runx2 and Smad1 disrupted the formation of the FRE-protein complex. These findings demonstrate that Ca(OH)(2) stimulates BSP transcription by targeting the CRE1, CRE2 and FRE elements in the human BSP gene promoter.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    AB5728

  • Calcium channels are involved in calcium oxalate crystal formation in specialized cells of Pistia stratiotes L. 15087302

    Pistia stratiotes produces large amounts of calcium (Ca) oxalate crystals in specialized cells called crystal idioblasts. The potential involvement of Ca(2+) channels in Ca oxalate crystal formation by crystal idioblasts was investigated.Anatomical, ultrastructural and physiological analyses were used on plants, fresh or fixed tissues, or protoplasts. Ca(2+) uptake by protoplasts was measured with (45)Ca(2+), and the effect of Ca(2+) channel blockers studied in intact plants. Labelled Ca(2+) channel blockers and a channel protein antibody were used to determine if Ca(2+) channels were associated with crystal idioblasts.(45)Ca(2+) uptake was more than two orders of magnitude greater for crystal idioblast protoplasts than mesophyll protoplasts, and idioblast number increased when medium Ca was increased. Plants grown on media containing 1-50 microM of the Ca(2+) channel blockers, isradipine, nifedipine or fluspirilene, showed almost complete inhibition of crystal formation. When fresh tissue sections were treated with the fluorescent dihydropyridine-type Ca(2+) channel blocker, DM-Bodipy-DHP, crystal idioblasts were intensely labelled compared with surrounding mesophyll, and the label appeared to be associated with the plasma membrane and the endoplasmic reticulum, which is shown to be abundant in idioblasts. An antibody to a mammalian Ca(2+) channel alpha1 subunit recognized a single band in a microsomal protein fraction but not soluble protein fraction on western blots, and it selectively and heavily labelled developing crystal idioblasts in tissue sections.The results demonstrate that Ca oxalate crystal idioblasts are enriched, relative to mesophyll cells, in dihydropyridine-type Ca(2+) channels and that the activity of these channels is important to transport and accumulation of Ca(2+) required for crystal formation.
    Dokumententyp:
    Referenz
    Produkbestellnummer:
    MAB427
    Produktbezeichnung:
    Anti-Dihydropyridine-sensitive Calcium Channel α 1 Subunit Antibody, clone 1a