Studies of phosphorus metabolism by isolated nuclei. XII. Some fundamental properties of the incorporation of 32Pi into polyphosphate by rat liver nuclei

1984 ◽  
Vol 4 (11) ◽  
pp. 957-962 ◽  
Author(s):  
Ralph Penniall ◽  
James B. Griffin
Keyword(s):  
Rat Liver ◽  
Phosphorus Metabolism ◽  
Preliminary Estimate ◽  
Isolated Nuclei ◽  
Fundamental Properties ◽  
Rat Liver Nuclei ◽  
Minimal Rate ◽  
Liver Nuclei ◽  
Insoluble Product

Rat liver nuclei incubated in vitro catalyze a sustained incorporation of32Pi into polyphosphate. A preliminary estimate indicates a minimal rate of 10 moles of Pi incorporation into polyphosphates/h/mg protein. Polyphosphate is the predominant acid-insoluble product of nuclear phosphorylation; its formation is dependent on the presence of a divalent cation and is catalyzed by a system or systems as yet uncharacterized.

scholarly journals Inhibition by α-amanitin of ribonucleic acid polymerase solubilized from rat liver nuclei

1970 ◽  
Vol 116 (2) ◽  
pp. 177-180 ◽  
Author(s):  
F. Novello ◽  
L. Fiume ◽  
F. Stirpe
Keyword(s):  
Rna Polymerase ◽  
Ammonium Sulphate ◽  
Rat Liver ◽  
Ribonucleic Acid ◽  
Isolated Rat Liver ◽  
Rat Liver Nuclei ◽  
Liver Nuclei ◽  
Isolated Rat

1. α-Amanitin inhibits in vitro the RNA polymerase solubilized from isolated rat liver nuclei. 2. In contrast with previous observations with whole nuclei, the inhibition occurs approximately to the same extent in the presence and in the absence of ammonium sulphate. 3. Evidence is presented that the toxin acts by interacting with the enzyme itself and not with DNA or other components.

scholarly journals Signal-dependent translocation of simian virus 40 large-T antigen into rat liver nuclei in a cell-free system.

1987 ◽  
Vol 7 (12) ◽  
pp. 4255-4265 ◽  
Author(s):  
W Markland ◽  
A E Smith ◽  
B L Roberts
Keyword(s):  
Rat Liver ◽  
Nuclear Translocation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Rat Liver Nuclei ◽  
Liver Nuclei

An in vitro nuclear translocation system is described in which isolated rat liver nuclei were incubated in a defined buffered medium containing radiolabeled or fluorescently labeled exogenous proteins. The nuclei were rapidly recovered, extracted, and analyzed for the presence of associated radiolabeled or fluorescently labeled proteins. The isolated nuclei exhibited the same specificity for protein uptake as seen previously in vivo, accumulating simian virus 40 wild-type large-T antigen and p53 while excluding a cytoplasmic variant of large-T antigen (d10) and bovine serum albumin. The rapid nuclear accumulation of wild-type large-T antigen was shown to be selective and dependent upon the recognition of a wild-type nuclear location signal, ATP and temperature dependent, and unidirectional. Taken together, the data suggest that in our in vitro system the nuclear translocation of wild-type large-T antigen exhibits some of the characteristics of an active transport process.

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