scholarly journals The effect of spermine on transcription of mammalian chromatin by mammalian deoxyribonucleic acid-dependent ribonucleic acid polymerase

1975 ◽  
Vol 146 (3) ◽  
pp. 697-703 ◽  
Author(s):  
G Moruzzi ◽  
B Barbiroli ◽  
M S Moruzzi ◽  
B Tadolini
Keyword(s):  
Polymerase Activity ◽  
E Coli ◽  
Biphasic Effect ◽  
Low Salt ◽  
Genome Transcription ◽  
Liver Chromatin ◽  
Rna Polymerase Activity ◽  
Liver Nuclei ◽  
Homologous Enzyme

Isolated rat liver nuclei demonstrate an increased ability to synthesize RNA in the presence of either spermine or spermidine. Spermidine has more effect on the low-salt α-amanitin-insensitive reaction, and spermine has more effect on the high-salt α-amanitin-sensitive reaction. Spermine is effective at concentrations of 0.1 mM and 1 muM, showing a biphasic effect. The RNA polymerase activity associated with nuclear chromatin is increased in the presence of spermine only at a concentration of 0.1 mM. Aso the transcription of deproteinized liver DNA by liver form-B polymerase or Escherichia coli enzyme is more efficient in the presence of 0.1 mM-spermine. Only when liver chromatin is transcribed by its homologous enzyme (and not by E. coli enzyme) is spermine active at both 0.1mM and 1 muM as in purified nuclei. The lower concentration of spermine (1 muM) is able to affect chromatin transcription by increasing the affinity of chromatin for the enzyme. Our findings suggest a regulatory role of spermine at the level of genome transcription.

A Possible Role of Lipids in RNA Polymerase from Mammalian Cells

1972 ◽  
Vol 50 (7) ◽  
pp. 807-812 ◽  
Author(s):  
I. A. Menon
Keyword(s):  
Rna Polymerase ◽  
Phospholipase D ◽  
Mammalian Cells ◽  
Polymerase Activity ◽  
Ionic Concentration ◽  
Phospholipase A ◽  
Rat Tissues ◽  
Rna Polymerase Activity ◽  
Liver Nuclei

The effects of treatment with phospholipases and extraction with solvents on the activities of RNA polymerases from several rat tissues were studied. The RNA polymerase activity of particulate enzyme from rat liver nuclei was decreased by pretreatment of the enzyme with phospholipase A. The phospholipase decreased the RNA polymerase activity in presence of Mg2+ but not that in presence of Mn2+. The effect of phospholipase A was observed only at low ionic concentration. When the RNA polymerase activity was determined in presence of ammonium sulfate, KCl, or NaCl, phospholipase A did not decrease the RNA polymerase activity. Extraction of the RNA polymerase with ether or iso-octane decreased the RNA polymerase activity to approximately the same extent as the pretreatment with phospholipase A. Phospholipase C produced similar changes as phospholipase A but phospholipase D and lipase did not have any effect on the RNA polymerase activity. Treatment with phospholipase A as well as extraction with solvents enhanced the activity of chromatin-bound RNA polymerase from rat brain, and the RNA polymerase activities of similar preparations from spleen, kidney, heart, and lung were affected only to a relatively smaller extent.

scholarly journals Transcription of brain chromatin by ribonucleic acid polymerases from brain nucleic and from Escherichia coli

1972 ◽  
Vol 130 (4) ◽  
pp. 1095-1099 ◽  
Author(s):  
Vijendra K. Singh ◽  
S. C. Sung
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Mammalian Cells ◽  
Transcriptional Control ◽  
Polymerase Activity ◽  
Control Mechanisms ◽  
E Coli ◽  
Bacterial Enzyme ◽  
Rna Polymerase Activity

1. Transcription of ox brain chromatin by brain nuclear RNA polymerase II and Escherichia coli RNA polymerase was studied. 2. The soluble chromatin prepared from brain nuclei contained DNA, RNA, histone and non-histone proteins. Such chromatin preparations did not display any endogenous RNA polymerase activity, when assayed in the presence of concentrations of KCl as high as 0.4m. 3. The chromatin-templated activity of brain nuclear polymerase II was stimulated by KCl, with an optimum around 0.25m. 4. The template activity of brain chromatin for brain nuclear polymerase II and E. coli enzyme was about 20–25% of that of pure DNA. This greatly repressed templatecapacity of chromatin was probably due to the acid-soluble chromosomal proteins. 5. Brain nuclear polymerase II was 3–4 times more active with dehistonized chromatin than with pure DNA as template, whereas bacterial enzyme was almost equally active with either of these two templates, reflecting the specificity of the transcriptional control mechanisms in mammalian cells.

scholarly journals Studies on ribonucleic acid and homopolyribonucleotide formation in neuronal, glial and liver nuclei

1970 ◽  
Vol 116 (4) ◽  
pp. 599-609 ◽  
Author(s):  
Takahiko Kato ◽  
Masanori Kurokawa
Keyword(s):  
White Matter ◽  
Guinea Pig ◽  
Rna Polymerase ◽  
Grey Matter ◽  
Polymerase Activity ◽  
Physical Relationship ◽  
Neuronal Nuclei ◽  
Cerebral Grey Matter ◽  
Rna Polymerase Activity ◽  
Liver Nuclei

1. Various types of nuclear preparations, with different ratios of neuronal to glial nuclei, were isolated from guinea-pig cerebral grey matter and ox cerebral grey matter and white matter. Conditions appropriate for the separate assay of RNA and poly A formation were described. Comparative rates of RNA and poly A formation were studied in cerebral and liver nuclei. 2. RNA polymerase activity per nucleus is higher in neuronal nuclei than in glial nuclei. In liver nuclei, the activity is much lower than in cerebral nuclei. The physical relationship between RNA polymerase and deoxyribonucleoprotein seems to differ in neuronal, glial and liver nuclei. 3. Poly A polymerase activity in liver nuclei is selectively activated by Mn2+ and inhibited by GTP, CTP and UTP. On a DNA basis, the activity in an aggregate enzyme is the same as in intact nuclei. Poly A polymerase activity per nucleus is much higher in liver nuclei than in neuronal nuclei. Glial nuclei show an intermediate activity. 4. It is suggested that, in neuronal nuclei, the synthesis of RNA is more prominent than that of poly A under conditions where both polymers are formed simultaneously. This contrasts with liver nuclei, where more poly A is made than RNA. 5. In neuronal nuclei, the rate of CTP incorporation is much higher than in glial and liver nuclei. This incorporation is most probably due to poly C synthesis.

scholarly journals Effect of hypophysectomy on liver nuclear ribonucleic acid synthesis in aging rats

1979 ◽  
Vol 184 (3) ◽  
pp. 669-674 ◽  
Author(s):  
R Bolla ◽  
W D Denckla
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Hormone Replacement ◽  
Polymerase Activity ◽  
Sprague Dawley ◽  
Age Related ◽  
Nuclear Rna ◽  
Rna Polymerase Activity ◽  
Liver Nuclei ◽  
Intact Rats

Changes in RNA synthesis in liver nuclei were observed at different ages and after hypophysectomy and hormone replacement in female Sprague-Dawley rats. As determined by the incorporation of [3H]UMP into an acid-insoluble product, RNA synthesis decreased by about 75% in intact rats from 6 months to 24 months of age. This decline with age was not observed in liver nuclei from 24-month-old rats that had been hypophysectomized at 12 months and maintained on a minimal hormone-replacement therapy. Thyroid hormones and somatotropin (growth hormone) had an additive effect on RNA synthesis in liver nuclei from these hypophysectomized rats. The same hormones had no significant effect on intact, age-matched rats. With advancing age, nuclei of intact rats had an increase in the pool of free RNA polymerase and an apparent decrease in the enzyme activity bound to nuclear chromatin. There was no change in total enzyme with age. In hypophysectomized, hormone-treated rats, free RNA polymerase activity decreased and chromatin-bound activity increased. There was no difference in total nuclear RNA polymerase activity between operated or intact rats. However, the ratio of the bound to the free activity was different. These results suggest that the ability of RNA polymerase to bind to chromatin may be involved in the age-related decrease in liver nuclear RNA synthesis of intact rats.

scholarly journals Modification of the template capacity of liver chromatin for form-B ribonucleic acid polymerase by food intake in rats under controlled feeding schedules

1975 ◽  
Vol 146 (3) ◽  
pp. 687-696 ◽  
Author(s):  
B Barbiroli ◽  
B Tadolini ◽  
M S Moruzzi ◽  
M G Monti
Keyword(s):  
Ionic Strength ◽  
Food Intake ◽  
Rna Polymerase ◽  
Dark Period ◽  
Polymerase Activity ◽  
Nuclear Chromatin ◽  
Feeding Period ◽  
Period 2 ◽  
Liver Chromatin ◽  
Rna Polymerase Activity

Nuclei from liver of rats accustomed to eating during the first 8h of a daily 12h dark period demonstrate an increased capacity to synthesize RNA 6H after the beginning of the feeding period. 2. This increase is accompanied by a higher yield of extractable form-B DNA-dependent RNA polymerase activity. 3. The endogenous RNA polymerase activity associated with nuclear chromatin is also stimulated by food intake. Both purified and chromatin-associated form-B enzyme activities exhibit different ionic strength requirements after food intake. 4. The sensitivity of exogenous (added) form-B-enzyme to changes in ionic strength changes after feeding when chromatin is used as template. 5. Chromatin extracted from the liver of fed rats is a better template for form-B-enzyme than chromatin extracted from starved rats.

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