Messenger RNA regulation in human diploid fibroblasts

Meedel, Thomas H.; Levine, Elliot M.

doi:10.1002/jcp.1040900207

Cited by 20 publications

(8 citation statements)

References 33 publications

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“…Since we find that less than 20% of newly formed ribosomal proteins are unstable, in any growth condition, the absolute synthesis of ribosomal proteins must be coupled closely to that of ribosomal RNA. This is consistent with the findings that the transcription of ribosomal RNA is reduced by half in stationary cells (Holley and Kiernan, 1968;Mauck and Green, 1974;Meedel and Levine, 1976) but is stimulated immediately on the addition of serum (Mauck and Green, 1973).…”

Section: Discussionsupporting

confidence: 91%

“…Ribosomal protein synthesis in nongrowing 3T3 cells Serum-deprived mouse 3T3 cells synthesize protein at a substantially slower rate than growing cells (Mauck and Green, 1973;Rudland, 1974). This is due partly to the sequestering of mRNA in untranslated form (Bandman and Gurney, 1975;Meedel and Levine, 1976), but it may be related as well to a reduced concentration of ribosomes Stanners et al, 1979). To determine whether the reduction in ribosomes was due in part to areduction in the synthesis of ribosomal 130 TUSHINSKI AND WARNER proteins, the synthesis of ribosomal proteins was compared with that of histones and other nonribosomal proteins under growing and nongrowing conditions.…”

Section: Resultsmentioning

confidence: 99%

“…Ribosomes turn over in stationary normal cells; they are stable in transformed cells (Meedel and Levine, 1978). Ribosomal RNA transcription is reduced by 50% or more in stationary normal cells (Holley and Kiernan, 1968;Mauck and Green, 1974;Meedel and Levine, 1976;Liebhaber et al, 1978). Interestingly, however, under all conditions the processing of ribosomal precursor RNA occurs efficiently, resulting in little wastage of RNA (Liebhaber et al, 1978).…”

Section: Discussionmentioning

confidence: 99%

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Ribosomal proteins are synthesized preferentially in cells commencing growth

Tushinski¹,

Warner²

1982

Journal Cellular Physiology

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Mouse 3T3 cells, in stationary phase because of serum deprivation, have only half the ribosome content of growing cells. Furthermore, the proportion of protein synthesis devoted to ribosomal proteins is only half that in growing cells. On addition of serum the synthesis of each ribosomal protein increases threefold, demonstrating the coordination of the synthesis of the ribosomal proteins. Half that increase is due to a general increase in total protein synthesis; half is due to a differential increase in ribosomal protein synthesis. The latter is abolished by a concentration of actinomycin D which blocks only ribosomal RNA transcription. The results are discussed with reference to a general hypothesis of growth regulation proposed by Stanners et al. (1979).

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Section: Discussionsupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Ribosomal proteins are synthesized preferentially in cells commencing growth

Tushinski¹,

Warner²

1982

Journal Cellular Physiology

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“…as the rate of cell division declines, there is a significant decrease in the rate of ribosomal RNA synthesis (12) and an increase in the rate of ribosomal RNA degradation (12, 37,66). There is also a decrease in the ribosome content in the cell (3,15,41), as well as a decrease in the relative specific activity of elongation factor I and several amino acyl-tRNA synthetases (15). In other words, at a time when the rate of cellular protein synthesis is decreasing, there is a general stepdown of the protein synthetic machinery.…”

mentioning

confidence: 99%

“…In other words, at a time when the rate of cellular protein synthesis is decreasing, there is a general stepdown of the protein synthetic machinery. Furthermore, the proportion of ribosomes that are not engaged in protein synthesis is increased (15, 36,37,49,50,59), and also cytoplasmic potyadenylated RNA is accumulated in the nonpolysomal fraction of stationary phase cells (2,41,49,50). These nonpolysomal polyadenylated RNA species and nontranslating ribosomes can be driven into the polysomal fraction in the presence of a low dose of cycloheximide (2,16,58).…”

mentioning

confidence: 99%

Growth-related fluctuation in messenger RNA utilization in animal cells.

Lee¹,

Engelhardt²

1978

The Journal of Cell Biology

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Monkey fibroblasts maintained in culture regulate their levels of intracellular protein throughout the growth cycle by means of variations in the rate of protein biosynthesis. Cytoplasmic mRNA in stationary phase cells was compared to that in exponential phase cells. In stationary phase cells 56% of the cytoplasmic polyadenylated RNA was found in the 40-90S postpolysomal region of sucrose sedimentation gradients, while only 23% was found in this region in exponential phase cells. Analysis of electron micrographs of sectioned exponential and stationary phase cells revealed that this shift in polyadenylated RNA location is accompanied by a loss of polysome-like aggregates of ribosomes. Most if not all of this species of postpolysomal polyadenylated RNA is not being translated by single ribosomes since no detectable amounts of nascent peptide were present in this region. This nonpolysomal polyadenylated RNA is comparable in size to polysomal polyadenylated RNA. The length of the 3'-poly(A) tract was also comparable for these two species. The extent of capping of poly(A)-containing molecules was also comparable for these two species. The template activity of nonpolysomal RNA in a wheat germ extract was comparable to that of polysomal RNA. The peptides produced by these two preparations were of a similar large size. Furthermore, most of the nonpolysomal polyadenylated RNA of stationary phase cells was driven into polysomes in the presence of a low dose of cycloheximide. Therefore, we conclude that the untranslated mRNA that accumulates in stationary phase cells is structurally intact, is fully capable of being translated, and is not being translated due to the operation of a translational initiation block.

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Regulation of protein synthesis in human diploid fibroblasts: Reduced initiation efficiency in resting cultures

Meedel

Levine

1978

Journal Cellular Physiology

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The level of poly A+ RNA in growing cultures of human diploid fibroblasts is 1.8-fold times greater than in resting cultures. The level of functional ribosomes in growing cultures is 2.8 times that in resting cultures. Since transit times are similar in both types of cells, it can be concluded that the rate of protein synthesis in growing cultures is 2.8 times that in resting cultures. a reduced efficiency of mRNA translation at the level of initiation in resting cultures is proposed as a probable explanation for the fact that the decrease in protein synthesis rates is greater than the decrease in mRNA levels. This hypothesis is supported by the observations that: (a) poly A+ RNA is associated with smaller polysomes in resting than in growing cells, and (b) cycloheximide treatment of resting cells results in recruitment of nonpolysomal poly A+ RNA into polysomes and a shift of polysomal poly A+ RNA into larger polysomes.

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Messenger RNA regulation in human diploid fibroblasts

Cited by 20 publications

References 33 publications

Ribosomal proteins are synthesized preferentially in cells commencing growth

Ribosomal proteins are synthesized preferentially in cells commencing growth

Growth-related fluctuation in messenger RNA utilization in animal cells.

Regulation of protein synthesis in human diploid fibroblasts: Reduced initiation efficiency in resting cultures

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