Nuclear Distribution of Prothymosin α and Parathymosin: Evidence That Prothymosin α Is Associated with RNA Synthesis Processing and Parathymosin with Early DNA Replication

2000 ◽  
Vol 257 (1) ◽  
pp. 152-161 ◽  
Author(s):  
Katerina Vareli ◽  
Maria Frangou-Lazaridis ◽  
Ineke van der Kraan ◽  
Orestes Tsolas ◽  
Roel van Driel
Keyword(s):  
Dna Replication ◽  
Rna Synthesis ◽  
Prothymosin Α ◽  
Nuclear Distribution

Wachstumsparameter in normalen und durch Actinomycin verlängerten Zellzyklen von Tetrahymena / Growth Parameters in Normal and Actinomycin-induced prolonged Cell Cycles of Tetrahymena

1969 ◽  
Vol 24 (12) ◽  
pp. 1624-1629 ◽  
Author(s):  
Günter Cleffmann
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Growth ◽  
Rna Synthesis ◽  
Growth Parameters ◽  
Average Duration ◽  
Cell Cycles ◽  
Growing Cell

Actinomycin in low concentration (0,2 μg/ml — 0,5 μg/ml) prolongs the average duration of the cell cycle of Tetrahymena considerably, but does not inhibit cell division completely. Some parameters of the growing cell have been tested in cell cycles extended in this way and compared to those of normally growing cells. The RNA synthesis of treated cells is reduced to such an extent that the RNA content per cell decreases during the prolonged cell cycle. Nevertheless cell growth, protein synthesis and DNA replication proceed at almost the same rate as in untreated cells. These findings indicate that the presence of actinomycin does not interfere with RNA fractions necessary for growth but reduce the synthesis of RNA fractions which are essential for cell division. Therefore a longer period is needed for their accumulation.

Interaction between natural compounds and human topoisomerase I

2012 ◽  
Vol 393 (11) ◽  
pp. 1327-1340 ◽  
Author(s):  
Silvia Castelli ◽  
Andrea Coletta ◽  
Ilda D’Annessa ◽  
Paola Fiorani ◽  
Cinzia Tesauro ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Dna Replication ◽  
Topoisomerase I ◽  
Rna Synthesis ◽  
Natural Compounds ◽  
Dna And Rna ◽  
Cellular Target ◽  
Dna And Rna Synthesis ◽  
Medical Interest ◽  
Different Levels

Abstract Eukaryotic topoisomerase I (Top1) is a monomeric enzyme that catalyzes the relaxation of supercoiled DNA during important processes including DNA replication, transcription, recombination and chromosome condensation. Human Top1 I is of significant medical interest since it is the unique cellular target of camptothecin (CPT), a plant alkaloid that rapidly blocks both DNA and RNA synthesis. In this review, together with CPT, we point out the interaction between human Top1 and some natural compounds, such us terpenoids, flavonoids, stilbenes and fatty acids. The drugs can interact with the enzyme at different levels perturbing the binding, cleavage, rotation or religation processes. Here we focus on different assays that can be used to identify the catalytic step of the enzyme inhibited by different natural compounds.

RNA synthesis in polyoma virus-infected cells. I. Pattern of formation of polyribosome-associated messenger RNA during productive infection

1970 ◽  
Vol 48 (10) ◽  
pp. 1104-1112 ◽  
Author(s):  
William P. Cheevers ◽  
Rose Sheinin
Keyword(s):  
Dna Replication ◽  
Messenger Rna ◽  
Rna Synthesis ◽  
Polyoma Virus ◽  
Productive Infection ◽  
Mrna Synthesis ◽  
Viral Dna ◽  
Experimental Conditions ◽  
Embryo Cells ◽  
Infected Cells

Experimental conditions have been established for selective measurement of the synthesis of mRNA in mouse embryo cells. Using such conditions, it was found that productive infection of these cells by polyoma virus resulted in stimulation of mRNA synthesis. The pattern of induction of mRNA synthesis was biphasic, characterized by distinct "early" and "late" periods, as denoted by the time of initiation of progeny viral DNA replication. The formation of "early" mRNA was first detected at 9–11 h postinfection, 6 h prior to the time of onset of virus-induced synthesis of cell DNA and 9 h prior to initiation of polyoma DNA replication. The initiation of synthesis of "late" mRNA was approximately coincident with the onset of formation of viral DNA. Most of the newly synthesized "early" and "late" mRNA was of relatively small size (8–12 S) and was associated with polyribosomes which sedimented at less than 180 S. The proportion of the total "late" mRNA which was virus-specific was three times higher than that of the total "early" mRNA; however, the mRNA synthesized both "early" and "late" was predominantly cell-specific.

scholarly journals Effect of multiple copies ofrpoBCon the rate of RNA synthesis inEscherichia coli

1986 ◽  
Vol 48 (2) ◽  
pp. 61-64 ◽  
Author(s):  
Elena C. Guzman ◽  
Alfonso Jimenez-Sanchez
Keyword(s):  
Dna Replication ◽  
Rna Polymerase ◽  
Rna Synthesis ◽  
Synthetic Activity ◽  
Gene Products ◽  
Replication Forks ◽  
E Coli ◽  
Multiple Copies ◽  
Autogenous Regulation ◽  
Rate Of Movement

SummaryThe cloning of therpoBandrpoCgenes in a high copy number vector inE. coliincreased the amount of the encoded gene products, the β and β′ subunits of RNA polymerase. However, this unexpectedly caused a 30–50% decrease in RNA synthetic activity which alternatively induced a reduction of growth rate and enlargement of cell size, and decreased the DNA replication time. The results can be explained by autogenous regulation of the RNA polymerase genes by the ββ′ subunits. A relation between the decrease in number of transcription units and the observed higher rate of movement of DNA replication forks is discussed.

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