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Nuclear DNA
About: Nuclear DNA is a research topic. Over the lifetime, 3933 publications have been published within this topic receiving 185830 citations.
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TL;DR: The recent discovery of a eukaryotic structural and functional differentiation in the dinochromosomes and of the organization of gene expression in them, demonstrate that in spite of the secondary loss of histones, that produce a lack of nucleosomal and supranucleosomal chromatin organization, they keep a functional nuclear organization closer to eUKaryotes than to prokaryotes.
86 citations
TL;DR: The intracellular migration of polymerase from the cytoplasm to the nucleus is suggested as a mechanism to account for early development results in sea urchin embryos.
86 citations
TL;DR: Analysis of viral DNA and RNA synthesis in infected cells by electron microscopic autoradiography and biochemical techniques supports the conclusion that FV 3 DNA synthesis is initiated in the nucleus and completed in the cytoplasm.
86 citations
TL;DR: A chemoptogenetic approach that uses a mitochondrially targeted fluorogen-activating peptide (Mito-FAP) to deliver a photosensitizer MG-2I dye exclusively to this organelle induces mitochondrial dysfunction by generating short-lived highly reactive singlet oxygen exclusively in the mitochondria, with precise spatiotemporal control by light stimulation.
Abstract: Reactive oxygen species (ROS) play important roles in aging, inflammation, and cancer. Mitochondria are an important source of ROS; however, the spatiotemporal ROS events underlying oxidative cellular damage from dysfunctional mitochondria remain unresolved. To this end, we have developed and validated a chemoptogenetic approach that uses a mitochondrially targeted fluorogen-activating peptide (Mito-FAP) to deliver a photosensitizer MG-2I dye exclusively to this organelle. Light-mediated activation (660 nm) of the Mito-FAP–MG-2I complex led to a rapid loss of mitochondrial respiration, decreased electron transport chain complex activity, and mitochondrial fragmentation. Importantly, one round of singlet oxygen produced a persistent secondary wave of mitochondrial superoxide and hydrogen peroxide lasting for over 48 h after the initial insult. By following ROS intermediates, we were able to detect hydrogen peroxide in the nucleus through ratiometric analysis of the oxidation of nuclear cysteine residues. Despite mitochondrial DNA (mtDNA) damage and nuclear oxidative stress induced by dysfunctional mitochondria, there was a lack of gross nuclear DNA strand breaks and apoptosis. Targeted telomere analysis revealed fragile telomeres and telomere loss as well as 53BP1-positive telomere dysfunction-induced foci (TIFs), indicating that DNA double-strand breaks occurred exclusively in telomeres as a direct consequence of mitochondrial dysfunction. These telomere defects activated ataxia-telangiectasia mutated (ATM)-mediated DNA damage repair signaling. Furthermore, ATM inhibition exacerbated the Mito-FAP–induced mitochondrial dysfunction and sensitized cells to apoptotic cell death. This profound sensitivity of telomeres through hydrogen peroxide induced by dysregulated mitochondria reveals a crucial mechanism of telomere–mitochondria communication underlying the pathophysiological role of mitochondrial ROS in human diseases.
86 citations
TL;DR: G+C-rich satellite DNA, representing about 19% of total nuclear DNA, was isolated from various tissues of the monocotyledonous plant, Scilla siberica, by using Ag(+)-Cs(2)SO(4) gradient techniques and suggests that this constitutively methylated sequence is evolutionarily stable.
Abstract: G+C-rich satellite DNA, representing about 19% of total nuclear DNA, was isolated from various tissues of the monocotyledonous plant, Scilla siberica, by using Ag+-Cs2SO4 gradient techniques. This satellite DNA had an unusually high melting point and a high methylcytosine (m5C) content (≈25% of total bases; m5C/cytosine ratio ≈1.5) and was localized, by in situ hybridization, in the heterochromatin regions of the chromosomes. Digestion with restriction endonuclease Hae III yielded a series of fragments ranging from 35 to several hundred nucleotide pairs. The major fragments, I-IV (35, 50, 59, and 69, nucleotide pairs, respectively), were isolated, and their nucleotide sequences were determined. The dominant fragment I was a highly symmetrical molecule, with a basically palindromic arrangement. This sequence represented the basic unit of Scilla satellite DNA and was tandemly repeated many times, with some base substitutions and multiple successive insertions of the tetranucleotide G-T-C-C. The dinucleotide CpG was the commonest nearest-neighbor sequence. Thin layer chromatography, DNA sequence analysis, and gas chromatography combined with mass spectrometry showed the high m5C content (m5C/Cyt = 2.2 and 2.8, respectively, for fragments II and III). Identical cleavage fragments were found in satellite DNAs from two other species of this genus (S. amoena and S. ingridae), which suggests that this constitutively methylated sequence is evolutionarily stable. The sequence arrangement of this plant satellite DNA is compared with those reported for several animal satellite DNAs.
86 citations