scholarly journals THE SYNTHESES OF DEOXYRIBONUCLEIC ACID AND HISTONE IN THE ONION ROOT MERISTEM

1967 ◽  
Vol 33 (3) ◽  
pp. 451-467 ◽  
Author(s):  
David P. Bloch ◽  
Robert A. MacQuigg ◽  
Sheilah D. Brack ◽  
Jung-Rung Wu
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Root Meristem ◽  
The Other ◽  
Chromosomal Protein ◽  
Chromosomal Proteins ◽  
Onion Root ◽  
Histone Synthesis ◽  
The Times

A comparison of the times necessary to incorporate tritium-labeled lysine and arginine into histones and tritium-labeled thymidine into DNA indicates that the periods of DNA and histone synthesis prior to division closely coincide. (The comparison was made by determining the times necessary, after pulse labeling, for cells with marked chromosomes to enter and then leave the division stages.) An additional period of chromosomal protein synthesis, of short duration, occurs late in interphase. Most of the chromosomal proteins appear either to be synthesized in the nucleus or to migrate there shortly after synthesis. Much of this protein is conserved from one division to the next. Studies of the effects of puromycin and fluorodeoxyuridine on the syntheses of DNA and histone suggest that continuation of DNA synthesis is dependent on a concurrent protein synthesis. Histone synthesis, on the other hand, can proceed at a normal rate under conditions in which DNA synthesis is inhibited.

scholarly journals THE SYNTHESIS OF ACIDIC CHROMOSOMAL PROTEINS DURING THE CELL CYCLE OF HELA S-3 CELLS

1972 ◽  
Vol 52 (2) ◽  
pp. 308-315 ◽  
Author(s):  
T. W. Borun ◽  
G. S. Stein
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Protein Fraction ◽  
Polyacrylamide Gel ◽  
Nuclear Fraction ◽  
Chromosomal Protein ◽  
Chromosomal Proteins ◽  
Kinetics Of ◽  
Mitotic Cells

The kinetics of acidic residual chromosomal protein synthesis and transport were studied throughout the cell cycle in HeLa S-3 cells synchronized by 2 mM thymidine block and selective detachment of mitotic cells. Pulse labeling the cells with leucine-3H for 2 min and then "chasing" the radioactive proteins for up to 3 hr showed that the amount of protein synthesized, transported, and retained in the acidic residual chromosomal protein fraction is greater immediately after mitosis and later in G1 than in the S or G2 phases of the cell cycle. During S, only 20–25% of the proteins synthesized and transported to the acidic residual chromosomal protein fraction are chased during the first 2 hr after pulse labeling, whereas up to 40% of the material entering the residual nuclear fraction in mitosis, G1, and G2 leaves during a 2 hr chase. Polyacrylamide gel electrophoretic profiles of these proteins, at various times after pulse labeling, reveal that the turnover of individual polypeptides within this fraction has kinetics of synthesis and turnover which are markedly different from one another and undergo stage-specific changes.

scholarly journals Schedule of Spermatogenesis in the Pulmonate Snail Helix aspersa, with Special Reference to Histone Transition

1960 ◽  
Vol 7 (3) ◽  
pp. 515-531 ◽  
Author(s):  
David P. Bloch ◽  
Howard Y. C. Hew
Keyword(s):  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Chromosome Duplication ◽  
Staining Methods ◽  
Histone Synthesis ◽  
Pass Through ◽  
The Times ◽  
Snail Helix Aspersa ◽  
New Protein

The schedule of spermatogenesis is determined from the times necessary for cells labeled with tritium thymidine during premeiotic DNA synthesis to pass through the successive spermatogenic stages. A transition from a typically somatic histone rich in lysine, to a histone rich in arginine is shown to occur during spermatid stages. A later shift to a protamine is observed in the maturing sperm. These changes are characterized by the use of in situ staining methods. The transition to an arginine-rich histone is accompanied by incorporation of tritium-labeled arginine, hence reflects synthesis of new protein. Comparison of the timing of arginine and thymidine incorporation, and independent measurements of DNA, show that in contrast to the case of premitotic chromosome duplication, the histone synthesis in the spermatid is unaccompanied by DNA synthesis. During the initial histone change, fine filaments are formed within the nucleus, which aggregate to form lamellae. This fine structure is lost during maturation of the sperm.

Timing of Nucleolar Activity in Meristems

1972 ◽  
Vol 11 (3) ◽  
pp. 713-721
Author(s):  
C. DE LA TORRE ◽  
F. A. CLOWES
Keyword(s):  
Zea Mays ◽  
Protein Synthesis ◽  
Dna Synthesis ◽  
Mitotic Cycle ◽  
Root Meristem ◽  
Quiescent Centre ◽  
Nucleolar Activity ◽  
Previous Cycle ◽  
Nucleolar Cycle ◽  
Rna Genes

The nucleoli in 4 regions of the root meristem of Zea mays have been examined and the time spent in each of the phases of the nucleolar cycle has been calculated from estimates of the rates of mitosis and the fraction of cycling cells in each region. The nucleolar cycles have been fitted to the mitotic cycles of cycling cells in the same regions. The timing of activity of the r-RNA genes differs in relation to the chromosomal cycles of condensation and movement in the different regions of the meristem. In the stelar regions disorganization of the nucleolus starts in the middle of prophase and reorganization starts towards the end of telophase and is completed in the following interphase. In the quiescent centre of the meristem the phases of both cycles are lengthened except for telophase and reorganization of the nucleolus does not start until after the end of telophase. The acceleration of telophase in the quiescent centre is discussed in relation to inhibition of protein synthesis. In the adjacent cap initials, which have the shortest mitotic cycle, the nucleolus starts to disorganize before the onset of prophase and reorganization is completed halfway through telophase. This fits with the fact that DNA synthesis is advanced into the telophase of the previous cycle in these cells.

scholarly journals Interrelationships of protein and DNA syntheses during replication of mammalian cells.

1985 ◽  
Vol 5 (6) ◽  
pp. 1279-1286 ◽  
Author(s):  
E Sariban ◽  
R S Wu ◽  
L C Erickson ◽  
W M Bonner
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Mrna Levels ◽  
Histone Protein ◽  
Ovary Cells ◽  
Histone Synthesis ◽  
Dna Components

During the replication of chromatin, the syntheses of the histone protein and DNA components are closely coordinated but not totally linked. The interrelationships of total protein synthesis, histone protein synthesis, DNA synthesis, and mRNA levels have been investigated in Chinese hamster ovary cells subjected to several different types of inhibitors in several different temporal combinations. The results from these studies and results reported elsewhere can be brought together into a consistent framework which combines the idea of autoregulation of histone biosynthesis as originally proposed by W. B. Butler and G. C. Mueller (Biochim. Biophys. Acta 294:481-496, 1973] with the presence of basal histone synthesis and the effects of protein synthesis on DNA synthesis. The proposed framework obviates the difficulties of Butler and Mueller's model and may have wider application in understanding the control of cell growth.

scholarly journals SYNTHESIS OF DEOXYRIBONUCLEIC ACID BY MICRO- AND MACRONUCLEI OF TETRAHYMENA PYRIFORMIS

1962 ◽  
Vol 13 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Barbara B. McDonald
Keyword(s):  
Dna Synthesis ◽  
Generation Time ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Tetrahymena Pyriformis ◽  
Type Ii ◽  
Total Period ◽  
Daughter Cells ◽  
Generation Times ◽  
The Times

Evidence as to the times of DNA synthesis in micronucleate Tetrahymena pyriformis (mating type II, variety 1) has been obtained by briefly exposing individuals of different ages to tritiated thymidine, returning them to non-radioactive medium, fixing at division, and preparing autoradiographs. A variable length of interphase, ranging from a few minutes to about 2 hours, has been found to precede the initiation of macronuclear DNA synthesis. Once begun, however, the period of synthesis appears to be similar in all cells, regardless of generation time, and has been estimated at 1 to 1½ hours. Under the conditions of these experiments, the time elapsing between the end of synthesis and subsequent division into daughter cells ranges from approximately 1½ to 2½ hours in generation times long enough to allow such variability. Division of the micronucleus occurs shortly before the cell begins to divide; its DNA synthesis starts immediately and continues after cell division for a total period estimated at about an hour.

Interrelationships of protein and DNA syntheses during replication of mammalian cells

1985 ◽  
Vol 5 (6) ◽  
pp. 1279-1286
Author(s):  
E Sariban ◽  
R S Wu ◽  
L C Erickson ◽  
W M Bonner
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Mrna Levels ◽  
Histone Protein ◽  
Ovary Cells ◽  
Histone Synthesis ◽  
Dna Components

During the replication of chromatin, the syntheses of the histone protein and DNA components are closely coordinated but not totally linked. The interrelationships of total protein synthesis, histone protein synthesis, DNA synthesis, and mRNA levels have been investigated in Chinese hamster ovary cells subjected to several different types of inhibitors in several different temporal combinations. The results from these studies and results reported elsewhere can be brought together into a consistent framework which combines the idea of autoregulation of histone biosynthesis as originally proposed by W. B. Butler and G. C. Mueller (Biochim. Biophys. Acta 294:481-496, 1973] with the presence of basal histone synthesis and the effects of protein synthesis on DNA synthesis. The proposed framework obviates the difficulties of Butler and Mueller's model and may have wider application in understanding the control of cell growth.

scholarly journals Accumulation of O6-methylguanine in non-target-tissue deoxyribonucleic acid during chronic administration of dimethylnitrosamine

1977 ◽  
Vol 165 (3) ◽  
pp. 463-468 ◽  
Author(s):  
G P Margison ◽  
J M Margison ◽  
R Montesano
Keyword(s):  
Dna Repair ◽  
Dna Synthesis ◽  
Acid Hydrolysis ◽  
Deoxyribonucleic Acid ◽  
Chronic Administration ◽  
The Other ◽  
Target Tissue ◽  
Mild Acid Hydrolysis ◽  
Stomach Tube ◽  
Mild Acid

1. BD-IV rats were given labelled dimethylnitrosamine (2 mg/kg) by stomach tube on weekdays (Monday to Friday) for up to 24 weeks. The rats killed after 2, 4, 8, 16 and 24 weeks of treatment (72 h after the final dimethylnitrosamine gavage) and DNA was isolated from the pooled livers, kidneys and lungs. Purine bases were released from the DNA by mild acid hydrolysis and separated by Sephadex G-10 chromatography. 2. Throughout the experiment, the content of 7-methylguanine in liver DNA was approx. 16 times that in kidney and lung. The amount of this product increased in the DNA of all three tissues up to 16 weeks, but by 24 weeks had decreased by 20% in the liver and 46% in the other tissues. 3. O6-Methylguanine was not detected in liver DNA, but was easily measured in kidney and lung DNA after 4 weeks of dimethylnitrosamine administration. The amount of O6-methylguanine in kidney and lung DNA increased relative to that of 7-methylguanine, and by 24 weeks was 60% of the 7-methylguanine content in both tissues. 4. Incorporation of radioactive C1 breakdown products of dimethylnitrosamine into normal purines in DNA increased continuously in all three tissues. 5. The results are discussed with respect to the specific hepatocarcinogenic effect of chronic administration of dimethylnitrosamine and the possible contribution of increased DNA repair and DNA synthesis.

scholarly journals DNA REPLICATION PATTERNS AND CHROMOSOMAL PROTEIN SYNTHESIS IN OPOSSUM LYMPHOCYTES IN VITRO

1967 ◽  
Vol 33 (3) ◽  
pp. 497-509 ◽  
Author(s):  
Lawrence K. Schneider ◽  
William O. Rieke
Keyword(s):  
Protein Synthesis ◽  
Dna Replication ◽  
Dna Synthesis ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Didelphis Virginiana ◽  
Chromosomal Protein ◽  
Large Size ◽  
Mitotic Figures

DNA replication patterns were determined in the autosomes and sex chromosomes of phytohemagglutinin-stimulated lymphocytes from the opossum (Didelphis virginiana) by employing thymidine-3H labeling and high-resolution radioautography. Opossum chromosomes are desirable experimental material due to their large size, low number (2n = 22), and morphologically distinct sex chromosomes. The autosomes in both sexes began DNA synthesis synchronously and terminated replication asynchronously. One female X chromosome synthesized DNA throughout most of the S phase. Its homologue, however, began replication approximately 3.5 hr later. The two X's terminated DNA synthesis synchronously, slightly later than the autosomes. This form of late replication, in which one X chromosome begins DNA synthesis later than its homologue but completes replication at the same time as its homologue, is apparently unique in the opossum. The male X synthesized DNA throughout S while the Y chromosome exhibited late-replicating characteristics. The two sex chromosomes completed synthesis synchronously, slightly later than the autosomes. Grain counts were performed on all chromosomes to analyze trends in labeling intensity at hourly intervals of S. By analyzing the percent of labeled mitotic figures on radioautographs at various intervals after introduction of arginine-3H, chromosomal protein synthesis was found not to be restricted to any portion of interphase but to increase throughout S and into G2.

Sign in / Sign up

Export Citation Format

Share Document