Nuclear fraction

PKA activity is present throughout the cell, associated with the plasma membrane as well as cytoplasmic and nuclear fractions. The kinase is highly compartmentalized within the cell, in large part via a series of anchoring... 

The intracellular distribution of steroid hormone receptors has long been the object of controversy. The first theoretical formulation on the intracellular location of the ERs was elaborated by Jensen in 1968 and is known as the two-step theory. Its execution was based entirely on biochemical observations obtained by means of tritium-marked estradiol. The ERs, in cells not exposed to hormones, are found abundantly in the soluble cell fraction, or cytosol (Fig. 1.1). Treatment with hormones confines the receptors to the particulated or nuclear fraction and causes their disappearance from the cytosol. The two-step theory established that the receptor is found in the cytoplasm naturally and upon the arrival of a hormone it is transformed into a complex hormone-receptor (first step) capable of translocating itself to the nucleus and of modifying gene expression (second step). 

Centrifuge the rc-homogem/ed deposit ai MX) lot ID min as before. Remove the supernatant lluid (II) and tesuspend die deposit in ihc same volume of buffer as was originally usfri (XmlV-This is the nuclear fraction. 

Although glucose-6-phosphatase activity in the nuclear fraction which has generally been observed may in part result from contamination of nuclear preparations with unruptured cells and debris, activity has also been observed with purified nuclei (62). Further, Kashnig and Kasper (63) have recently identified glucose-6-phosphatase as a component of rat liver nuclear membrane. 

Heavy oils and residua can be separated into a variety of fractions using a myriad of different techniques that have been used since the beginning of petroleum science (Speight, 1999). However, the evolution of these techniques has been accompanied by subtle inter-laboratory (and even intra-laboratory) variations to an extent that many of the nuclear fractionation procedures appear to bear very little relationship to one another. 

The Triton X-100 lysis method [9] is relatively simple and is a cost-effective method. To 10 mL of blood, 90 mL of cold (4°C) RBC lysis buffer (0.32 M sucrose, 10 mM Tris-Cl, pH 7.5, 5 mM MgCL, 1% Triton X-100) is added and mixed by inverting the tube a few times. This step releases cellular contents, and the crude nuclear fraction containing the DNA is then centrifuged at 3500 x g at 4°C for 30 minutes. The supernatant is decanted and the pellet is resuspended in a small volume of cold RBC buffer by vor-texing and brought upto 40 mL with the same buffer and recentrifuged as... 

To isolate RNA from cellular fractions such as nuclear or cytoplasm, the first step is to isolate that particular cell fraction. During the fractionation process, caution is exercised not to contaminate one fraction with another. The crude nuclear fraction is often contaminated with mitochondria and endoplasmic reticulum, both of which carry their RNA components. Hence it is highly desirable to further purify the nuclear fraction before isolating the RNA. 

Cupers, P., Orlans, I., Craessaerts, K., Annaert, W. and de Strooper, B. (2001) The amyloid precursor protein (APP)-cytoplasmic fragment generated by gamma-secretase is rapidly degraded but distributes partially in a nuclear fraction of neurones in culture, J. Neurochem. 78, 1168. 

Attempts to determine the intracellular distribution of acid phosphatase in the prostate must take into account the presence of this enzyme in the extracellular secretion. Employing centrifugal methods, Siebert et al. (S20) found that of the total acid phosphatase present in bull prostate homogenate, 0.7% was in the nuclear fraction, 41% in the mitochondrial fraction which presumably included the lysosomal component, and 84% in the microsomal and supernatant components. The finding that the sum of these activities exceeded that in the homogenate was considered to represent removal of inhibitors during separation of the fractions. 

Dapas B, Tell G, Scaloni A, Pines A, Ferrara L, Quadrifoglio F, Scaggiante B. Identification of different isoforms of eEFlA in the nuclear fraction of human T-lymphoblastic cancer cell line specifically binding to aptameric cytotoxic GT oligomers. Eur J Biochem 2003 270(15) 3251-62. 

Dl. Depierre, J. W., and Karnovsky, M. L., Isolation of a nuclear fraction from guinea pig polymorphonuclear leukocytes after controlled hypotonic homogenization. Biochim. Biophys. Acta 320, 205-209 (1973). 

Rushmore, T. H., Lim, Y. R, Farber, E., and Ghoshal, A. K., Rapid lipid peroxidation in the nuclear fraction of rat liver induced by a diet deficient in choline and methionine, Cancer Lett., 24, 251, 1984. 

In the case of GC1, modest selectivity for THRp has been described (6.6-fold) which originates from the oxyaceticacid head group [55], In vivo, an increase in selectivity is achieved by accumulation in the liver versus the heart. Ciba-Geigy (now Novartis) discovered the lipid-lowering thyromimetic CGS 26214 devoid of cardiac and thermogenic activity. CGS 26214 was identified based on its ability to access and bind to the nuclear fraction of hepatocytes about 100-fold better compared to that of myocytes in culture. Similar characteristics were reported for L-94901 which was developed by SK F. It was suggested that the liver selectivity of L-94901 is achieved... 

Fig. 8.4 Schematic diagram illustrating methods for quantifying the subcellular distribution of plasmid DNA (pDNA). After the transfection of rhodamine-labeled pDNA, the endosome/lysosome fraction and nuclear fraction was stained with LysoSenser DND-189 and Hoechst 33342, respectively to discriminate the subcellular localization of pDNA. For the data analysis, the pixel areas of each cluster on plasma membrane, S (mem), endosomes/lysosomes, Sj(end/lys), cytosol s, (cyt) and nucleus S (nuc) were separately summed in each XY-plane, and are denoted as S2 j(mem), S2 j(end/lys), S2 j(cyt) and S2 j(nuc), respectively. The values of S2 j(mem), S2 j(end/lys), and S j(nuc) in each X-Y plane were further summed and are denoted as...

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