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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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Journal ArticleDOI
TL;DR: An Arabidopsis cell-free system is developed that can be used to monitor biochemical and morphological changes in isolated nuclei that are associated with PCD and suggests the presence of an Mg2+-dependent nuclease activity in the intermembrane space is responsible for the former in vitro activity.
Abstract: The key role for mitochondria in mammalian apoptosis, a form of programmed cell death (PCD), is well established, but a similar role for plant mitochondria is just emerging. In order to unravel the molecular mechanisms linking plant mitochondria to the downstream events of PCD, we have developed an Arabidopsis cell-free system that can be used to monitor biochemical and morphological changes in isolated nuclei that are associated with PCD. Using this system, two activities that resulted in nuclear DNA degradation could be distinguished, both of which were facilitated by the addition of mitochondria. One activity mediated the generation of 30 kb DNA fragments within 3 h and chromatin condensation within 6 h, when nuclei were incubated with mitochondria alone. The second activity required cytosolic extract in addition to mitochondria and resulted in oligonucleosome-sized DNA cleavage after >12 h. Submitochondrial fractionation and pharmacological studies suggested the presence of an Mg2+-dependent nuclease activity in the intermembrane space, which is responsible for the former in vitro activity. The evolutionary conservation of the role of mitochondria in PCD in animals and plants is discussed.

116 citations

Journal Article
TL;DR: There is increased mtDNA damage in aged RPE and choroid, which is likely due to decreased DNA repair capability, which may be a susceptibility factor that underlies the development of AMD.
Abstract: Purpose: In the central nervous system (CNS), increased mitochondrial DNA (mtDNA) damage is associated with aging and may underlie, contribute to, or increase the susceptibility to neurodegenerative diseases. Because of the focus on the retinal pigment epithelium (RPE) and choroid as tissue relevant to age-related macular degeneration (AMD), we examined young and aged RPE and choroid, harvested from rodent eyes, for DNA damage and for changes in selected DNA repair enzymes. Methods: Immunohistochemical labeling and quantitative ELISA for the oxidative DNA damage marker, 8-hydroxy-2’deoxy-guanosine (8-OHdG), were measured in young and aged rodent RPE and choroid. mtDNA and nuclear DNA (nDNA) damage was determined by quantitative polymerase chain reaction (PCR) by comparing the relative amplification of small and large DNA fragments. Expression of several DNA repair enzymes was measured using real-time quantitative reverse transcription -PCR (qRT–PCR) and immunoblot. Results: Immunohistochemical labeling for 8-OHdG increased in aged rodent RPE and choroid. Quantitative ELISA confirmed increased levels of 8-OHdG. Measurements of nDNA and mtDNA lesions indicated that DNA damage is primarily in mtDNA in aged RPE and choroid. Using qRT–PCR, we found that gene expression of DNA repair enzymes, 8-oxoguanine-DNA glycosylase 1 (OGG1), mutY homolog (MYH), and thymine DNA glycosylase were decreased in an age-dependent pattern in RPE and choroid. However, endonuclease III homolog 1 was not significantly changed in aged RPE and choroid. Using immunoblots, we found that protein levels of OGG1 and MYH were decreased in aged RPE and choroid. Conclusions: Our results show that there is increased mtDNA damage in aged RPE and choroid, which is likely due to decreased DNA repair capability. mtDNA damage in the RPE and choroid may be a susceptibility factor that underlies the development of AMD.

115 citations

Journal ArticleDOI
TL;DR: It is shown that meiosis is a normal part of development in the insect salivary glands for all subspecies of Trypanosoma brucei, including the human pathogens.

115 citations

Journal ArticleDOI
TL;DR: This work compared six sets of nuclear and mitochondrial noncoding DNA sequences of primates and obtained the estimates of the evolutionary rate of insertion and deletion, and the maximum-parsimony principle was applied to locate insertions and deletions on a given phylogenetic tree.
Abstract: Insertions and deletions are responsible for gaps in aligned nucleotide sequences, but they have been usually ignored when the number of nucleotide substitutions was estimated. We compared six sets of nuclear and mitochondrial noncoding DNA sequences of primates and obtained the estimates of the evolutionary rate of insertion and deletion. The maximum-parsimony principle was applied to locate insertions and deletions on a given phylogenetic tree. Deletions were about twice as frequent as insertions for nuclear DNA, and single-nucleotide insertions and deletions were the most frequent in all events. The rate of insertion and deletion was found to be rather constant among branches of the phylogenetic tree, and the rate (approximately 2.0/kb/Myr) for mitochondrial DNA was found to be much higher than that (approximately 0.2/kb/Myr) for nuclear DNA. The rates of nucleotide substitution were about 10 times higher than the rate of insertion and deletion for both nuclear and mitochondrial DNA.

115 citations

Journal ArticleDOI
TL;DR: Electron microscopic analysis of chloroplast DNA, purified in CsCl or Cscl/ethidium bromide gradients, revealed up to 80% circular molecules, which are comparable to the size derived for the coding capacity of chloroplasts from reassociation experiments.

115 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202361
202284
202177
202064
201966
201862