scholarly journals Half-life and rate of synthesis of globin messenger ribonucleic acid. Determination of half-life of messenger ribonucleic acid and its relative synthetic rate in erythroid cells

1974 ◽  
Vol 138 (3) ◽  
pp. 487-498 ◽  
Author(s):  
John A. Hunt
Keyword(s):  
Cell Division ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Specific Radioactivity ◽  
Erythroid Cells ◽  
Mrna Synthesis ◽  
Messenger Ribonucleic Acid ◽  
Mrna Half Life ◽  
Division Model ◽  
Basophilic Erythroblast

The specific radioactivity of mouse globin mRNA in blood reticulocytes was measured after injection of [3H]uridine into anaemic mice up to 60h before collection of reticulocytes. From these data, the decay of the acid-soluble nucleotide pool in the marrow and the relative marrow-cell composition it is possible to build models that allow the cell life-times and half-life of mRNA in the erythroid cells of the marrow to be calculated. Best fit of models to these data favour a model with either one or two cell divisions from the onset of mRNA synthesis. The single-cell-division model has cell times of 20, 13 and 7h respectively for the basophilic erythroblast, polychromatophilic erythroblast and reticulocyte. The two-cell-division model has cell times of 12, 12, 12 and 7h for the basophilic erythroblast 1 and 2, polychromatophilic erythroblast and reticulocyte respectively. Both models have an mRNA half-life of 17h and a constant rate of mRNA synthesis until enucleation at the reticulocyte stage, when synthesis stops. A declining rate of mRNA synthesis can be accommodated in a two-cell-division model, when synthesis halves at each cell division and cell times are essentially the same as above, but mRNA half-life is either 9h in the basophilic and polychromatophilic erythroblasts and 17h in the later cells, or 10h in the basophilic erythroblasts and polychromatophilic erythroblasts and 14.5h in later cells. In all cases it is clear that mRNA synthesis occurs over a time-period of only 30–36h and that mRNA cannot be pre-synthesized in precursor erythroid cells.

scholarly journals Rate of synthesis and half-life of globin messenger ribonucleic acid. Rate of synthesis of globin messenger ribonucleic acid calculated from data of cell haemoglobin content

1974 ◽  
Vol 138 (3) ◽  
pp. 499-510 ◽  
Author(s):  
John A. Hunt
Keyword(s):  
Ribonucleic Acid ◽  
Half Life ◽  
Chain Elongation ◽  
Erythroid Cell ◽  
Synthesis Rate ◽  
Mrna Synthesis ◽  
Base Pairs ◽  
Messenger Ribonucleic Acid ◽  
Nucleotide Base ◽  
Mrna Half Life

By the use of the favoured models defining mRNA synthesis and half-life from the preceding paper (Hunt, 1974) and the known content of globin in a reticulocyte it is possible to estimate the absolute rate of mRNA and globin synthesis and the mRNA and globin content in each type of erythroid cell. The best model requires an mRNA-synthetic rate of 3000 molecules per h/cell. This rate compares favourably with the estimated chain-extension rate of 43 nucleotides/s in Escherichia coli (Manor et al., 1969) provided that the four α- and β-chain cistrons per cell are transcribed by polymerases spaced 50 nucleotide base pairs apart. Similar calculations can be made for erythropoiesis in the chick embryo, where cell times and relative globin content at each mitosis have been measured (Campbell et al., 1971), but where no reliable estimates of mRNA half-life have been made. In this case it was estimated that a constant rate of mRNA synthesis at 10000 molecules per h/cell through six cell divisions is necessary if the mRNA half-life is 15h; after the sixth mitosis the mRNA synthesis would stop and its half-life would increase to approx. 20h. If an mRNA half-life of 4.5h is used, the synthesis rate through the six mitoses would be 21000 molecules per h/cell, ceasing at the sixth mitosis, when the half-life would need to increase to 25h. The chain-elongation rate for the four α- and β-globin cistrons per cell would be 1–2 times higher than in E. coli and would either require a greater rate, polymerases spaced between 25 and 50 nucleotide base pairs apart on the DNA, or limited gene replication. These possibilities are discussed in the light of the low values found for globin cistron multiplicity in ducks and mice.

scholarly journals Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable.

1981 ◽  
Vol 1 (6) ◽  
pp. 497-511 ◽  
Author(s):  
R Gelfand ◽  
G Attardi
Keyword(s):  
Ribosomal Rna ◽  
Hela Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Messenger Rna ◽  
Specific Activity ◽  
Mitochondrial Rna ◽  
Messenger Rnas ◽  
Precursor Pool ◽  
Messenger Ribonucleic Acid

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing

1981 ◽  
Vol 1 (2) ◽  
pp. 188-198
Author(s):  
M M Harpold ◽  
M C Wilson ◽  
J E Darnell
Keyword(s):  
Cho Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Large Fraction ◽  
Chinese Hamster ◽  
Great Majority ◽  
Molecular Probes ◽  
Processing Efficiency ◽  
Messenger Ribonucleic Acid ◽  
Nuclear Processing

We have further analyzed the metabolism of specific messenger ribonucleic acid (mRNA) sequences within the cytoplasmic and nuclear RNA of Chinese hamster ovary (CHO) cells by using a set of previously constructed complementary deoxyribonucleic acid (DNA) clones (Harpold et al., Cell 17:1025-1035, 1979) as specific molecular probes in a variety of RNA:DNA hybridization experiments. The majority of the labeled mRNA complementary to each of the nine clones was found in the polyribosomes, with some variation between individual sequences. The great majority of each specific mRNA labeled for 3 h or less was in the polyadenylated [poly(A)+] fraction. However, the amount of each sequence increased in the non-poly(A)+ [poly(A)-] fraction after very long label times, suggesting the derivation of the poly(A)- RNA from the poly(A)+ RNA. Eight of the nine mRNA's have cytoplasmic half-lives ranging from 8 to 14 h, whereas one of the mRNA's, the scarcest in the group, has a somewhat shorter half-life of approximately 3 h. The proportion of each of the specific long-lived mRNA's within the total labeled mRNA increased as a function of labeling time, indicating that a large fraction, probably greater than 50%, of the initially labeled poly(A)+ mRNA in CHO cells has a half-life of less than 3 h. A quantitative analysis of the kinetics of labeling of specific nuclear and cytoplasmic sequences indicated that a significant fraction of the mRNA sequences transcribed from genes containing these nine CHO sequences were successfully processed into mRNA. However, two of the CHO mRNA sequences were only partially conserved during nuclear processing to yield mRNA. These studies demonstrated that events at two post-transcriptional levels, differential nuclear processing efficiency of different primary transcripts and cytoplasmic stability of different mRNA's, can be involved in the determination of the cytoplasmic concentrations of different mRNA's.

scholarly journals Specific changes in the messenger ribonucleic acid content of the rat ventral prostate gland after androgenic stimulation. Evidence from the synthesis of aldolase messenger ribonucleic acid

1974 ◽  
Vol 144 (2) ◽  
pp. 413-426 ◽  
Author(s):  
W I P Mainwaring ◽  
F R Mangan ◽  
R A Irving ◽  
D A Jones
Keyword(s):  
Ribonucleic Acid ◽  
De Novo ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Mrna Synthesis ◽  
Hormonal Stimulation ◽  
Messenger Ribonucleic Acid ◽  
Stimulation Of

1. Aldolase was selected as a suitable marker for following the androgenic regulation of mRNA synthesis in the prostate gland. 2. Antibodies raised in rabbits against crystalline prostate aldolase were used to monitor the synthesis of this androgen-induced enzyme after hormonal stimulation of castrated animals, by using procedures in vivo and in vitro for the translation of prostate poly(A)-rich mRNA. 3. After androgenic stimulation in vivo the poly(A)-rich mRNA was isolated from the prostate gland and other tissues of castrated rats, and added to a protein-synthesizing system in vitro derived from Krebs II ascites-tumour cells. By using this approach it was found that androgens regulate the synthesis of aldolase mRNA in a highly tissue-specific manner. Stimulation of aldolase mRNA synthesis reached a maximum after 8h of androgenic treatment and then declined. 4. The androgenic control of aldolase mRNA synthesis was also investigated in vivo. After treatment of castrated animals with various steroids in vivo [35S]methionine was injected directly into the prostate gland, and labelled aldolase was selectively precipitated from isolated polyribosomes with anti-aldolase serum. The regulation of aldolase mRNA synthesis in the prostate gland was stringently steroid-specific and could only be evoked by androgens. After a single injection of testosterone, aldolase synthesis reached a maximum after 16h of hormonal stimulation and then declined. 5. Although androgens exert significant control over transcriptional processes in the prostate gland, and appear to regulate the synthesis of aldolase mRNA de novo, the possibility exists for additional means of control at the translational level of aldolase synthesis. The results are discussed in the context of the overall mechanism of action of androgens.

scholarly journals Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

1981 ◽  
Vol 1 (2) ◽  
pp. 188-198 ◽  
Author(s):  
M M Harpold ◽  
M C Wilson ◽  
J E Darnell
Keyword(s):  
Cho Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Large Fraction ◽  
Chinese Hamster ◽  
Great Majority ◽  
Molecular Probes ◽  
Processing Efficiency ◽  
Messenger Ribonucleic Acid ◽  
Nuclear Processing

We have further analyzed the metabolism of specific messenger ribonucleic acid (mRNA) sequences within the cytoplasmic and nuclear RNA of Chinese hamster ovary (CHO) cells by using a set of previously constructed complementary deoxyribonucleic acid (DNA) clones (Harpold et al., Cell 17:1025-1035, 1979) as specific molecular probes in a variety of RNA:DNA hybridization experiments. The majority of the labeled mRNA complementary to each of the nine clones was found in the polyribosomes, with some variation between individual sequences. The great majority of each specific mRNA labeled for 3 h or less was in the polyadenylated [poly(A)+] fraction. However, the amount of each sequence increased in the non-poly(A)+ [poly(A)-] fraction after very long label times, suggesting the derivation of the poly(A)- RNA from the poly(A)+ RNA. Eight of the nine mRNA's have cytoplasmic half-lives ranging from 8 to 14 h, whereas one of the mRNA's, the scarcest in the group, has a somewhat shorter half-life of approximately 3 h. The proportion of each of the specific long-lived mRNA's within the total labeled mRNA increased as a function of labeling time, indicating that a large fraction, probably greater than 50%, of the initially labeled poly(A)+ mRNA in CHO cells has a half-life of less than 3 h. A quantitative analysis of the kinetics of labeling of specific nuclear and cytoplasmic sequences indicated that a significant fraction of the mRNA sequences transcribed from genes containing these nine CHO sequences were successfully processed into mRNA. However, two of the CHO mRNA sequences were only partially conserved during nuclear processing to yield mRNA. These studies demonstrated that events at two post-transcriptional levels, differential nuclear processing efficiency of different primary transcripts and cytoplasmic stability of different mRNA's, can be involved in the determination of the cytoplasmic concentrations of different mRNA's.

Determination of mRNA Half-Life in HeLa Cultures by a Poly(A)-Independent Direct Analysis of Specific Radioactivity of mRNA

1975 ◽  
Vol 50 (3) ◽  
pp. 557-562 ◽  
Author(s):  
Ulrich WIEGERS ◽  
Gisela KRAMER ◽  
Karin KLAPPROTH ◽  
Wolfgang REHPENNING ◽  
Helmuth HILZ
Keyword(s):  
Half Life ◽  
Specific Radioactivity ◽  
Direct Analysis ◽  
Mrna Half Life

scholarly journals Determinants that contribute to cytoplasmic stability of human c-fos and beta-globin mRNAs are located at several sites in each mRNA.

1988 ◽  
Vol 8 (8) ◽  
pp. 3244-3250 ◽  
Author(s):  
K S Kabnick ◽  
D E Housman
Keyword(s):  
Half Life ◽  
Untranslated Region ◽  
Calf Serum ◽  
Beta Globin ◽  
Mrna Synthesis ◽  
Globin Mrna ◽  
Mrna Species ◽  
Quiescent Cells ◽  
The Stability ◽  
Mrna Half Life

We have analyzed the contributions to cytoplasmic stability in an mRNA species with a very short half-life (human c-fos) and an mRNA species with a very long half-life (human beta-globin). When the human c-fos promoter was used to drive the expression of human c-fos, beta-globin, and chimeric DNAs between c-fos and beta-globin in transfected cells, a pulse of mRNA synthesis was obtained following induction of transcription by refeeding quiescent cells with medium containing 15% calf serum. The mRNA half-life was determined by using Northern (RNA) blot analysis of mRNAs prepared at various times following the pulse of transcription. Under these conditions human c-fos mRNA exhibited a half-life of 6.6 min and human beta-globin mRNA exhibited a half-life of 17.5 h. Replacement of the 3' end of the c-fos mRNA with the 3' end of the beta-globin mRNA increased the half-life of the resultant RNA from 6.6 to 34 min. The reciprocal chimera had a half-life of 34.6 min compared with the 17.5-h half-life of beta-globin mRNA. These results suggest that sequences which make a major contribution to mRNA stability reside in the 3' end of either or both molecules. A chimera in which the 5' untranslated region of globin was replaced by part of the 5' untranslated region of fos led to destabilization of the encoded mRNA. This construct produced an mRNA with a half-life of 6.8 h instead of the 17.5-h half-life of globin. This result suggests that additional determinants of stability reside in the 5' end of these mRNA molecules. Substitution of part of the 5' untranslated region of fos by the 5' untranslated region of beta-globin yielded an mRNA with stability similar to fos mRNA. These results suggest that interactions among sequences within each mRNA contribute to the stability of the respective molecules.

scholarly journals Synthesis and turnover of mitochondrial ribonucleic acid in HeLa cells: the mature ribosomal and messenger ribonucleic acid species are metabolically unstable

1981 ◽  
Vol 1 (6) ◽  
pp. 497-511
Author(s):  
R Gelfand ◽  
G Attardi
Keyword(s):  
Ribosomal Rna ◽  
Hela Cells ◽  
Ribonucleic Acid ◽  
Half Life ◽  
Messenger Rna ◽  
Specific Activity ◽  
Mitochondrial Rna ◽  
Messenger Rnas ◽  
Precursor Pool ◽  
Messenger Ribonucleic Acid

The synthesis rates and half-lives of the individual mitochondrial ribosomal ribonucleic acid (RNA) and polyadenylic acid-containing RNA species in HeLa cells have been determined by analyzing their kinetics of labeling with [5-3H]-uridine and the changes in specific activity of the mitochondrial nucleotide precursor pools. In one experiment, a novel method for determining the nucleotide precursor pool specific activities, using nascent RNA chains, has been utilized. All mitochondrial RNA species analyzed were found to be metabolically unstable, with half-lives of 2.5 to 3.5 h for the two ribosomal RNA components and between 25 and 90 min for the various putative messenger RNAs. A cordycepin "chase" experiment yielded half-life values for the messenger RNA species which were, in general, larger by a factor of 1.5 to 2.5 than those estimated in the labeling kinetics experiments. On the basis of previous observations, a model is proposed whereby the rate of mitochondrial RNA decay is under feedback control by some mechanism linked to RNA synthesis or processing. A short half-life was determined for five large polyadenylated RNAs, which are probably precursors of mature species. A rate of synthesis of one to two molecules per minute per cell was estimated for the various H-strand-coded messenger RNA species, and a rate of synthesis 50 to 100 times higher was estimated for the ribosomal RNA species. These data indicate that the major portion of the H-strand in each mitochondrial deoxyribonucleic acid molecule is transcribed very infrequently, possibly as rarely as once or twice per cell generation. Furthermore, these results are consistent with a previously proposed model of H-strand transcription in the form of a single polycistronic molecule.

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