The total volume of centromeres per nucleus varies widely within Triticum aestivum cv. Chinese Spring (7-fold) and between 11 higher plant species (24-fold). Such variation is closely correlated with nuclear DNA content, nuclear volume and, to a lesser extent, the total volume of nucleoli per nucleus. Centromere volume reflects minor intraspecific developmental fluctuations in nuclear size inde...

A protein required for the elongation of replicating intermediates of adenovirus (Ad) DNA to full length has been isolated and characterized. This factor, isolated from nuclear extracts of uninfected HeLa cells, has been designated nuclear factor II. In the presence of Ad DNA with proteins at each 5' end (Ad DNA-protein) and three proteins coded for by the Ad genome [the preterminal protein (pT...

The number of pore complexes per nucleus was determined for a wide variety of cultured cells selected for their variable DNA content over a range of 1-5,6000. The pore number was compared to DNA content, nuclear surface area, and nuclear volume. Values for pore frequency (pores/square micrometer) were relatively constant in the species studied. When the pore to DNA ratio was plotted against the...

The topology of repeated sequences in mouse plasmocytoma DNA was studied by high-resolution CsCl density gradient centrifugation and heterogeneous nuclear RNA.DNA hybridization. Satellite region DNA of plasmocytoma cells contains additional components and hybridizes specifically with entire heterogeneous nuclear RNA molecules. A linkage is demonstrated between the A+T-rich satellite sequences a...

It has been generally believed that oncoretroviruses are dependent on mitosis for efficient nuclear entry of viral DNA. We previously identified a nuclear localization signal in the integrase protein of an oncoretrovirus, avian sarcoma virus (ASV), suggesting an active import mechanism for the integrase-DNA complex (G. Kukolj, R. A. Katz, and A. M. Skalka, Gene 223:157-163, 1998). Here, we have...

Schizosaccharomyces pombe Pfh1p is an essential member of the Pif family of 5'-3' DNA helicases. The two Saccharomyces cerevisiae homologs, Pif1p and Rrm3p, function in nuclear DNA replication, telomere length regulation, and mitochondrial genome integrity. We demonstrate here the existence of multiple Pfh1p isoforms that localized to either nuclei or mitochondria. The catalytic activity of Pfh...

One of the long-standing mysteries in genomic evolution is the observation that much of the genome is composed of repetitive DNA, resulting in inter- and intraspecific variation in nuclear DNA content. Our discovery of a negative correlation between nuclear DNA content and flower size in Silene latifolia has been supported by our subsequent investigation of changes in DNA content as a correlate...

Mitochondrial DNA is an extranuclear genome normally maternally inherited through the oocyte. However, the use of nuclear transfer can result in both donor cell and recipient oocyte mitochondrial DNA persisting through to blastocyst and being transmitted to the offspring. The degree of donor mitochondrial DNA transmission appears to be random and currently no evidence exists to explain this phe...

Experimental evidence suggests that exposure of sea urchin gastrulae to 5-bromodeoxyuridine (BUdR), an analog of thymidine, causes a reduction in the rate of synthesis of some RNA species usually transcribed at this stage of development . In pulse-chase experiments, 3H (in gastrula stage 8-15S nuclear DNA labeled with BUdR3H) could not be chased, with unlabeled BUdR, into 20-60S size-range DNA ...

The isolation of chloroplast and nuclear DNA from dark- and light-grown, control- and 3-amino-1,2,4-triazole-treated wheat seedlings, Triticum vulgare, is described. Contrary to a previous report, we found that chloroplast and nuclear DNA had similar buoyant densities (1.702 grams per cubic centimeter) and that they could not be resolved by buoyant density centrifugation in CsCl. Difference in ...