Nuclear DNA

About: Nuclear DNA is a research topic. Over the lifetime, 3933 publications have been published within this topic receiving 185830 citations.

Dna content and evolution in the microseridinae

Abstract: A B S T R A C T Relative 2C nuclear DNA contents were microphotometrically determined from nuclei isolated from eight species of Microseris, four species of Agoseris, and Phalacroseris Bolanderi. The thirteen species are diploid (2n = 18) western North American members of the subtribe Microseridinae, tribe Cichorieae, of the family Compositae. A 7.7-fold variation in DNA content was detected. Phalacroseris has the highest DNA content and Agoseris heterophylla has the lowest. Within the genera Microseris and Agoseris, a 2.8- and 3.1-fold range in DNA content was detected. The higher values were from perennial species, and the lower values were from annual inbreeding species. Both evolutionary increases and decreases in nuclear DNA content have apparently occurred during the differentiation of the subtribe. DNA CONTENT per nucleus and per chromosome varies over 100-fold among vascular plants (Rees, 1972; Rees and Jones, 1972; Sparrow, Price, and Underbrink, 1972; Price, Sparrow, and Nauman, in press). Although polyploidy is responsible for some of the variation in nuclear DNA content, an approximate 65-fold range is found among diploid

Sea urchin nuclear DNA polymerase.

Abstract: Publisher Summary Sea urchin embryos are particularly well suited as a source of DNA polymerase. In the initial cell divisions after fertilization, the rate of DNA synthesis is about 60 times greater than in most other animal cells. This high DNA synthetic activity in the embryos is accompanied by a correspondingly high level of DNA polymerase activity. The biology of this enzyme during early development of the embryo has been studied. It is synthesized during oogenesis and present in the unfertilized egg cytoplasm. With each cell division after fertilization, more and more is sequestered in the nuclei until, by the blastula stage, the majority of the embryo's polymerase activity can be isolated with the nuclei. For this reason, the enzyme purification is started with the nuclear fraction. This chapter describes the enzyme activity in the nuclear homogenate and discusses the purification procedure. It is slightly modified to simplify some of the steps, based on the accumulated experience.

Decreased mitochondrial DNA content in blood samples of patients with stage I breast cancer

Abstract: Background Alterations of mitochondrial DNA (mtDNA) have been implicated in carcinogenesis. We developed an accurate multiplex quantitative real-time PCR for synchronized determination of mtDNA and nuclear DNA (nDNA). We sought to investigate whether mtDNA content in the peripheral blood of breast cancer patients is associated with clinical and pathological parameters.

Mitochondrial and nuclear DNA damage and repair in age-related macular degeneration.

Abstract: Aging and oxidative stress seem to be the most important factors in the pathogenesis of age-related macular degeneration (AMD), a condition affecting many elderly people in the developed world. However, aging is associated with the accumulation of oxidative damage in many biomolecules, including DNA. Furthermore, mitochondria may be especially important in this process because the reactive oxygen species produced in their electron transport chain can damage cellular components. Therefore, the cellular response to DNA damage, expressed mainly through DNA repair, may play an important role in AMD etiology. In several studies the increase in mitochondrial DNA (mtDNA) damage and mutations, and the decrease in the efficacy of DNA repair have been correlated with the occurrence and the stage of AMD. It has also been shown that mitochondrial DNA accumulates more DNA lesions than nuclear DNA in AMD. However, the DNA damage response in mitochondria is executed by nucleus-encoded proteins, and thus mutagenesis in nuclear DNA (nDNA) may affect the ability to respond to mutagenesis in its mitochondrial counterpart. We reported that lymphocytes from AMD patients displayed a higher amount of total endogenous basal and oxidative DNA damage, exhibited a higher sensitivity to hydrogen peroxide and UV radiation, and repaired the lesions induced by these factors less effectively than did cells from control individuals. We postulate that poor efficacy of DNA repair (i.e., is impaired above average for a particular age) when combined with the enhanced sensitivity of retinal pigment epithelium cells to environmental stress factors, contributes to the pathogenesis of AMD. Collectively, these data suggest that the cellular response to both mitochondrial and nuclear DNA damage may play an important role in AMD pathogenesis.