Project description:Voltage dependent anion channel 1 (VDAC1) is a multi-functional protein that regulates mitochondrial membrane potential, calcium regulation, and apoptosis. VDAC1 also interacts with a number of signaling pathways important for energy homeostasis and proteins involved in neurodegenerative diseases such as alpha-synuclein. To identify novel signaling pathways dependent upon VDAC1 protein in dopamine cells, we used CRISPR-Cas9 gene editing in rat immortalized dopaminergic N27 cells. Western blot confirmed that VDAC1 protein levels were reduced ~90%. Mitochondrial bioenergetics was assessed to determine if there was functional loss of mitochondrial function without VDAC1. Loss of VDAC1 resulted in lower ATP-linked and maximum respiration, and spare respiratory capacity. Transcriptomics was conducted in these cells to identify the pathways perturbed by loss of VDAC. This study sheds novel insight into the different regulatory roles mediated by VDAC1 in dopamine cells.
Project description:Our previous study has shown that the expression of voltage-dependent anion channel 1 (VDAC1) is closely related to the tumorigenesis and progression of HCC.Nevertheless, tumorigenesis and progression of HCC are complex processes, and the specific mechanism of VDAC1 affecting the proliferation and invasion of HCC has not yet been elucidated. To further study the role of downstream related molecules of VDAC1, we utilized the Affymetrix GeneChip system to analyze the downstream gene expression profile of VDAC1
Project description:U87 xenograft tumors treated with scrambled siRNA (Tas_73, Tas_78) or siRNA against VDAC1 (Tas_57, Tas_61) We used microarrays to detail the global effect of siRNA against VDAC1 on subcotenous xenograft U87 cells tumors
Project description:Mitochondria are subcellular organelles that are more than just the powerhouse of cells, they also dictate if a cell dies or survives. The mitochondrial outer-membrane voltage-dependent anion channel 1 (VDAC1) has been shown to play a crucial role in metabolism and apoptosis, however its involvement in ischemic pathologies and cancer is not clear. Transcriptome analysis of Vdac1-/- mouse embryonic fibroblasts (MEF) highlighted cancer and inflammation as top diesases but also activation of the HIF-1 signaling pathway in normoxia. HIF-1α protein was stable due to ROS accumulation that decreased respiration and glycolysis and maintained basal apoptosis. However, in hypoxia increased activation of ERK in combination with maintenance of respiration and increased glycolysis counterbalanced the deleterious effects of ROS, thereby allowing Vdac1-/- MEF to proliferate better than wild-type MEF. Xenografts of RAS-transformed Vdac1-/- MEF in mice showed stabilization of both HIF-1α and HIF-2α which led to blood vessel destabilization and a strong inflammatory response. Moreover, expression of Cdkn2a, a HIF-1-target and tumor suppressor gene, was strongly decreased. Consequently RAS-transformed Vdac1-/- MEF tumors grew faster than wild-type MEF tumors. These findings provide new perspectives into the understanding of VDAC1 in the function of mitochondria not only in cancer but also in inflammatory diseases. Profiling of VDAC1-/- and wild-type (Wt) Mouse Embryonic Fibroblasts (MEFs) was performed using whole genome mouse microarrays. in normoxic or hypoxic conditions. MEF (Wt and Vdac1-/-) were incubated in normoxia (Nx, ie: 20% O2) or hypoxia (Hx, ie: 1% O2) for 72h and then lysed prior to RNA isolation, labelling and hybridization on microarrays. One color experiment with 2 biological replicates (marked 1 or 2) of the 4 experimental conditions. One condition (MEF WT Nx2) has been removed from the statistical analysis after microarray quality check due to high background. Total of 7 samples.
Project description:Mitochondria are subcellular organelles that are more than just the powerhouse of cells, they also dictate if a cell dies or survives. The mitochondrial outer-membrane voltage-dependent anion channel 1 (VDAC1) has been shown to play a crucial role in metabolism and apoptosis, however its involvement in ischemic pathologies and cancer is not clear. Transcriptome analysis of Vdac1-/- mouse embryonic fibroblasts (MEF) highlighted cancer and inflammation as top diesases but also activation of the HIF-1 signaling pathway in normoxia. HIF-1α protein was stable due to ROS accumulation that decreased respiration and glycolysis and maintained basal apoptosis. However, in hypoxia increased activation of ERK in combination with maintenance of respiration and increased glycolysis counterbalanced the deleterious effects of ROS, thereby allowing Vdac1-/- MEF to proliferate better than wild-type MEF. Xenografts of RAS-transformed Vdac1-/- MEF in mice showed stabilization of both HIF-1α and HIF-2α which led to blood vessel destabilization and a strong inflammatory response. Moreover, expression of Cdkn2a, a HIF-1-target and tumor suppressor gene, was strongly decreased. Consequently RAS-transformed Vdac1-/- MEF tumors grew faster than wild-type MEF tumors. These findings provide new perspectives into the understanding of VDAC1 in the function of mitochondria not only in cancer but also in inflammatory diseases.
Project description:The nucleus is a definitive feature of eukaryotic cells, comprising twin bilamellar membranes, the inner and outer nuclear membranes, which separate the nucleoplasmic and cytoplasmic compartments. Nuclear pores, complex macromolecular assemblies that connect the two membranes, mediate communication between these compartments. To explore the morphology, topology, and dynamics of nuclei within living plant cells, we have developed a novel method of confocal laser scanning fluorescence microscopy under time-lapse conditions. This is used for the examination of the transgenic expression in Arabidopsis thaliana of a chimeric protein, comprising the GFP (Green-Fluorescent Protein of Aequorea victoria) translationally fused to an effective nuclear localization signal (NLS) and to beta-glucuronidase (GUS) from E. coli. This large protein is targeted to the nucleus and accumulates exclusively within the nucleoplasm. This article provides online access to movies that illustrate the remarkable and unusual properties displayed by the nuclei, including polymorphic shape changes and rapid, long-distance, intracellular movement. Movement is mediated by actin but not by tubulin; it therefore appears distinct from mechanisms of nuclear positioning and migration that have been reported for eukaryotes. The GFP-based assay is simple and of general applicability. It will be interesting to establish whether the novel type of dynamic behavior reported here, for higher plants, is observed in other eukaryotic organisms.
Project description:Plants use light as a source of energy for photosynthesis and as a source of environmental information perceived by photoreceptors. Testing whether plants can complete their cycle if light provides energy but no information about the environment requires a plant devoid of phytochromes because all photosynthetically active wavelengths activate phytochromes. Producing such a quintuple mutant of Arabidopsis thaliana has been challenging, but we were able to obtain it in the flowering locus T (ft) mutant background. The quintuple phytochrome mutant does not germinate in the FT background, but it germinates to some extent in the ft background. If germination problems are bypassed by the addition of gibberellins, the seedlings of the quintuple phytochrome mutant exposed to red light produce chlorophyll, indicating that phytochromes are not the sole red-light photoreceptors, but they become developmentally arrested shortly after the cotyledon stage. Blue light bypasses this blockage, rejecting the long-standing idea that the blue-light receptors cryptochromes cannot operate without phytochromes. After growth under white light, returning the quintuple phytochrome mutant to red light resulted in rapid senescence of already expanded leaves and severely impaired expansion of new leaves. We conclude that Arabidopsis development is stalled at several points in the presence of light suitable for photosynthesis but providing no photomorphogenic signal.
Project description:Here we use bisulfite conversion of RNA combined with high-throughput IIlumina sequencing (RBS-seq) to identify single-nucleotide resolution of m5C sites in ribosomal RNAs of all three sub-cellular transcriptomes in Arabidopsis thaliana. m5C sites in rRNAs were also anlyzed in Arabidopsis T-DNA knockouts for the RNA methyltransferases TRM4A, TRM4B, TRDMT1, NSUN5, NOP2A, NOP2B and NOP2C.