Topic
Nuclear DNA
About: Nuclear DNA is a research topic. Over the lifetime, 3933 publications have been published within this topic receiving 185830 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: This chapter presents the cytochemical and immunohistochemical methods that, in the experience, appear to be the most reliable for the correct identification of mitochondria on frozen tissue sections to illustrate their potential using specific examples, and to provide an updated version of the methods.
Abstract: Publisher Summary This chapter presents the cytochemical and immunohistochemical methods that, in the experience, appear to be the most reliable for the correct identification of mitochondria on frozen tissue sections, to illustrate their potential using specific examples, and to provide an updated version of the methods. Although the described protocols refer to muscle mitochondria, the methods described can be applied to any cell type. The mitochondria are the primary adenosine triphosphate (ATP)-generating organelles in all mammalian cells and they contain their own DNA (mtDNA), which is maternally inherited. The human mitochondrial genome contains genes encoding for thirteen subunits of different respiratory complexes. These include seven subunits of complex I (NADH dehydrogenase–ubiquinone oxidoreductase), one subunit of complex III (ubiquinone–cytochrome-c oxidoreductase), three subunits of complex IV (cytochrome-c oxidase (COX)), and two subunits of complex V (ATP synthase). Although mitochondria have their transcriptional and translational machinery, most of the proteins located within mitochondria are encoded by the nuclear DNA (nDNA). These nuclear gene products are synthesized on cytoplasmic ribosomes and are subsequently imported into the mitochondria.
201 citations
TL;DR: Tryptic peptides were resolved from the small subunit of highly purified Fraction I protein obtained from Nicotiana tabacum,Nicotiana glutinosa, NicOTiana glauca and four reciprocal, F1 hybrids and were inherited in a Mendelian manner.
200 citations
TL;DR: There are reasons to hypothesize that mitochondrial DNA suffers greater oxidation than nuclear DNA, and methods being developed by a number of workers are likely to surmount current obstacles and allow the hypothesis to be tested definitively.
Abstract: Almost a decade ago, based on analytical measurements of the oxidative DNA adduct 8-oxo-deoxyguanosine (oxo8dG), it was reported that mitochondrial DNA suffers greater endogenous oxidative damage than nuclear DNA. The subsequent discovery that somatic deletions of mitochondrial DNA occur in humans, and that they do so to the greatest extent in metabolically active tissues, strengthened the hypothesis that mitochondrial DNA is particularly susceptible to endogenous oxidative attack. This hypothesis was (and is) appealing for a number of reasons. Nevertheless, solid direct support for the hypothesis is lacking. Since the initial measurements, attempts to repeat the observation of greater oxidation of mitochondrial DNA have resulted in a range of measurements that spans over four orders of magnitude. Moreover, this range includes values that are as low as published values for nuclear DNA. In the last 2 years or so, it has become apparent that the quantification of oxidative DNA adducts is prone to artifactual oxidation. We have reported that the analysis of small quantities of DNA may be particularly susceptible to such interference. Because yields of mitochondrial DNA are generally low, a systematic artifact associated with low quantities of DNA may have elevated the apparent level of adduct oxo8dG in mitochondrial DNA relative to nuclear DNA in some studies. Whatever the cause for the experimental variation, the huge disparity between published measurements of oxidative damage makes it impossible to conclude that mitochondrial DNA suffers greater oxidation than nuclear DNA. Despite the present confusion, however, there are reasons to hypothesize that this is indeed the case. We briefly describe methods being developed by a number of workers that are likely to surmount current obstacles and allow the hypothesis to be tested definitively.
200 citations
TL;DR: It is concluded that the intact mitochondrial DNA of S. carlsbergensis and S. cerevisiae consists of a circular molecule with a contour length of approx.
200 citations
TL;DR: It is shown that the steady-state levels of oxo8dG in mouse tissues range from 180 to 360 lesions in the nuclear genome and from one to two lesions in 100 mitochondrial genomes, and that the level in nuclear DNA (nDNA) is almost one-hundredth of the level obtained using the classical phenol method.
Abstract: A major controversy in the area of DNA biochemistry concerns the actual in vivo levels of oxidative damage in DNA. We show here that 8-oxo-2-deoxyguanosine (oxo8dG) generation during DNA isolation is eliminated using the sodium iodide (NaI) isolation method and that the level of oxo8dG in nuclear DNA (nDNA) is almost one-hundredth of the level obtained using the classical phenol method. We found using NaI that the ratio of oxo8dG/10(5 )deoxyguanosine (dG) in nDNA isolated from mouse tissues ranged from 0.032 +/- 0.002 for liver to 0.015 +/- 0.003 for brain. We observed a significant increase (10-fold) in oxo8dG in nDNA isolated from liver tissue after 2 Gy of gamma-irradiation when NaI was used to isolate DNA. The turnover of oxo8dG in nDNA was rapid, e.g. disappearance of oxo8dG in the mouse liver in vivo after gamma-irradiation had a half-life of 11 min. The levels of oxo8dG in mitochondrial DNA isolated from liver, heart and brain were 6-, 16- and 23-fold higher than nDNA from these tissues. Thus, our results showed that the steady-state levels of oxo8dG in mouse tissues range from 180 to 360 lesions in the nuclear genome and from one to two lesions in 100 mitochondrial genomes.
199 citations