Late changes in the course of mitosis in a synchronized Chinese hamster cell culture after inhibition of RNA and protein synthesis

1978 ◽  
Vol 86 (1) ◽  
pp. 924-927
Author(s):  
L. S. Strochkova ◽  
I. A. Alov
Keyword(s):  
Cell Culture ◽  
Protein Synthesis ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Rna And Protein Synthesis

scholarly journals Temperature-Sensitive Chinese Hamster Fibroblast Mutant with a Defect in RNA Metabolism

1982 ◽  
Vol 2 (12) ◽  
pp. 1558-1573 ◽  
Author(s):  
Eric A. Wong ◽  
Immo E. Scheffler
Keyword(s):  
Protein Synthesis ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Temperature Sensitive ◽  
Chinese Hamster Fibroblast ◽  
Rna And Protein Synthesis ◽  
Shock Proteins ◽  
Short Time ◽  
Biosynthetic Machinery ◽  
Temperature Sensitive Phenotype

We describe a new temperature-sensitive mutant of Chinese hamster cell fibroblasts. After a shift to the nonpermissive temperature of 40.5°C, the rates of DNA, RNA, and protein synthesis declined rapidly (to ≤50% within 12 h) and the progression of unsynchronized cells through the cell cycle was affected. We believe that DNA synthesis came to a halt after a short time, because cells no longer entered the S phase. The decrease in protein synthesis at 40.5°C was shown to be a consequence of a decrease in the number of polysomes, whereas free 80S ribosomes accumulated. We concluded that the components of the protein biosynthetic machinery were intact (ribosomes and soluble factors), but synthesis was limited by a shortage of mRNA. The decline in mRNA production had a significant effect on the synthesis of proteins (e.g., heat shock proteins) translated from short-lived messages. We observed that both polyadenylated and nonpolyadenylated RNA syntheses declined at 40.5°C, whereas the synthesis of small RNAs (4 to 5S) was less reduced. The argument is made that the temperature-sensitive phenotype is the result of a defect affecting mRNA synthesis.

Temperature-Sensitive Chinese Hamster Fibroblast Mutant with a Defect in RNA Metabolism

1982 ◽  
Vol 2 (12) ◽  
pp. 1558-1573
Author(s):  
Eric A. Wong ◽  
Immo E. Scheffler
Keyword(s):  
Protein Synthesis ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Temperature Sensitive ◽  
Chinese Hamster Fibroblast ◽  
Rna And Protein Synthesis ◽  
Shock Proteins ◽  
Short Time ◽  
Biosynthetic Machinery ◽  
Temperature Sensitive Phenotype

We describe a new temperature-sensitive mutant of Chinese hamster cell fibroblasts. After a shift to the nonpermissive temperature of 40.5°C, the rates of DNA, RNA, and protein synthesis declined rapidly (to ≤50% within 12 h) and the progression of unsynchronized cells through the cell cycle was affected. We believe that DNA synthesis came to a halt after a short time, because cells no longer entered the S phase. The decrease in protein synthesis at 40.5°C was shown to be a consequence of a decrease in the number of polysomes, whereas free 80S ribosomes accumulated. We concluded that the components of the protein biosynthetic machinery were intact (ribosomes and soluble factors), but synthesis was limited by a shortage of mRNA. The decline in mRNA production had a significant effect on the synthesis of proteins (e.g., heat shock proteins) translated from short-lived messages. We observed that both polyadenylated and nonpolyadenylated RNA syntheses declined at 40.5°C, whereas the synthesis of small RNAs (4 to 5S) was less reduced. The argument is made that the temperature-sensitive phenotype is the result of a defect affecting mRNA synthesis.

Chinese hamster cell mutant with defective mitochondrial protein synthesis

Nature ◽  
1977 ◽  
Vol 268 (5615) ◽  
pp. 64-67 ◽  
Author(s):  
G. DITTA ◽  
K. SODERBERG ◽  
I. E. SCHEFFLER
Keyword(s):  
Protein Synthesis ◽  
Mitochondrial Protein ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Mitochondrial Protein Synthesis ◽  
Cell Mutant

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

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