Nuclear DNA

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

Variation in mitochondrial-dna levels in muscle from normal controls - is depletion of mtdna in patients with mitochondrial myopathy a distinct clinical syndrome

Abstract: Recent studies have identified a group of patients with cytochrome oxidase (COX) deficiency presenting in infancy associated with a deficiency of mtDNA in muscle or other affected tissue (Moraes et al 1991). We used a novel approach to compare the level of mitochondrial (mtDNA) compared to nuclear DNA in skeletal muscle from a group of patients and controls, based on dot blots that were hybridized with a mtDNA probe labelled with35S[dCTP] and a reference nuclear DNA probe labelled with [32P]dCTP.

Changes in nuclear DNA in normal and ascites tumor cells.

Abstract: It is a commonplace that the study of the nature and function of genes is fundamental in biology, and it is natural that we should give considerable attention to desoxyribose nucleic acid (DNA), whose close association with the chromosomes has been supported by much of the available evidence. Moreover, DNA can be isolated pure, and its chemical and physical properties in certain states are now fairly well understood. Interest in DNA has been further accentuated because it is one of the very few substances whose quantity can be measured in individual cells. Two optical methods are suitable for this quantitative measurement of DNA. In the first, we can make use of the natural absorption a t 260 mp due to the purines and pyrimidines of the nucleic acid molecule and, in the second, of the absorption a t 550 mp of the Feulgen DNA complex. The former requires a complicated ultraviolet microspectrophotometer and is not s p e d c for DNA, but is perhaps most useful in combination with other methods in studying the relationship of DNA to other cellular components. On the other hand, instruments for measuring Feulgen stain to various degrees of accuracy are generally available and have been extensively used for many problems. Before presenting our own results on the quantitative behavior of DK.4 in both normal cells and those of some ascites tumors of the mouse, we shall consider very briefly some of the views on the role of this component in the cell and then discuss a t greater length the factors that cause variation in the measured amount of DNA in individual nuclei, as an aid to extending the usefulness of these comparatively new methods of quantitative measurement in cell biology. The two main opinions concerning the function of DNA may he simplified as follows: on the one hand, it is thought that the units that maintain genetic continuity are of a DKA4-protein nature and that, therefore, all cells whose characteristics are transmitted from one cell generation to the next should contain an amount of DNA depending, within a given species, on the number of chromosomes present. In addition, the amount of DNA must a t some stage double if the cells are to divide and still maintain this basic quantity. On the other hand, it has been suggested that proteins may constitute the units that maintain genetic continuity and that DNA has some subsidiary function. Experimentally, this second and less orthodox hypothesis is supported by any variation Lrom the standard haploid amount of DNA that is not accounted for by (a) variation in chromosome number, (b) synthesis of DNA in preparation for division, or (c) errors in measurement. However, it has been an interesting characteristic of the history of DNA measurements, from the original