Control of Synthesis and Wastage of Ribosomal Ribonucleic Acid in Lymphocytes

Cooper, Herbert L.; Gibson, Evelyn M.

doi:10.1016/s0021-9258(18)61969-6

Cited by 71 publications

(9 citation statements)

References 23 publications

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“…4). Thus, intermediate erythroid cells reveal a disproportionate accumulation of newly synthesized 26S rRNA relative to 17S rRNA, a phenomenon similar to "ribosomal wastage" described in inactive iymphocytes (9)(10)(11), contact-inhibited fibroblasts (14), and cultured cells exposed to inhibitors of protein synthesis (15,53). The discrepancy observed between the labeling and A2a0 ratios of the two respective rRNA species and the decline in specific activity of rRNA can be correlated with a decreased level of rRNA synthesis in these cells and the presence in the cytoplasm of a relatively large, preexisting ribosomal population formed in and retained from the early erythroid stages.…”

Section: Quantitative and Qualitative Aspects Of Rna Synthesismentioning

confidence: 72%

“…Although ribosomal wastage has usually been described in cells grown in vitro (9-11, 14, 15, 53), the results of the present studies demonstrate the occurrence of a similar phenomenon in cells within the intact organism. It is interesting that, as in stationary phase iymphocytes and contact-inhibited fibroblasts (9)(10)(11)14), ribosomal wastage in newt erythroid cells appears to parallel a decrease in cellular growth rate (22,49). However, the data obtained have not been sufficient to permit a determination of the precise relationship of a decreased growth rate to ribosomal wastage in newt erythroid elements.…”

Section: Discussionmentioning

confidence: 99%

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Biochemical characterization of RNA and protein synthesis in erythrocyte development.

Grasso¹,

Chromey²,

Moxey³

1977

The Journal of Cell Biology

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Newts (Triturus cristatus) made anemic with acetylphenylhydrazine (APH) fail to regenerate erythrocytes (RBC's) immediately and exhibit a latent period of 1.5-2 wk during which animals lack RBC's and are aplastic. With the establishment of erythroid regeneration at 10-14 days, relatively homogeneous populations of successive erythropoietic stages occur in the blood. This feature makes possible biochemical analyses of events in early, intermediate, and late developmental stages, respectively, each of which can be obtained in vivo with minimal contamination by other stages. Previous studies have described a primitive cell population referred to as "erythroid precursor cells" (EPC's) which precedes the appearance of definitive erythroid elements. The present studies show that EPC's and early erythroid cells are engaged mainly in ribosomal production, including synthesis of rRNA and ribosomal proteins. Moreover, EPC's and early erythroid cells also synthesize tRNA and a presumed Hb-mRNA which has been identified by its sedimentation rate at 9-12 s and its content of-polyadenylic acid. In intermediate stages, there occurs a fourfold decrease in the level of RNA synthesis and, while rRNA continues to be formed, there is a disproportionate accumulation of the two major cytoplasmic rRNA species in favor of the large ribosomal subunit RNA. In late developmental stages, the level of RNA synthesis is markedly diminished with little or no evidence of formation of defined RNA classes. Correlated radioautographic and biochemical studies with radioactive 8-aminolevulinic acid and leucine indicate that EPC's and other early erythroid elements synthesize not only hemoglobin but also ferritin and ribosomal proteins. It is concluded that: (a) erythroid RNA synthesis is most pronounced in the early developmental stages, being manifested predominantly by rRNA production but including tRNA and HbmRNA; (b) intermediate developmental stages show both "ribosomal wastage" and decreased growth rate, marking a pivotal point between the transcriptional activities of early stages and translational activities of late stages; (c) EPC's represent a cell population already committed to RBC formation and are excluded from a role as the pluripotential stem cell.The process of erythrocyte (RBC)development derived from an undifferentiated hemopoietic occurs as a series of successive stages which are stem cell. Although functional and cytogenetic 206

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Section: Quantitative and Qualitative Aspects Of Rna Synthesismentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Biochemical characterization of RNA and protein synthesis in erythrocyte development.

Grasso¹,

Chromey²,

Moxey³

1977

The Journal of Cell Biology

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“…Although the function of the nucleolus has been fairly well elucidated (15), the interplay between its different ultrastructural components and their respective functions has been very difficult to study mainly because of the lack of an adequate method of nucleolar fractionation. However, studies of the role of the cell protein-synthesizing machinery in the control of ribosome biosynthesis have hinted that such controls may be not only at the level of the synthesis and assembly, but also at the level of the release of the 55S precursors from the nucleolus (3,4). Our results would be consistent with this view of the granular region as a pool of nearly completed 55S subunits and could be relevant to the observation that nucleoli of tumor cells have a greater proportion of granules than normal cells…”

Section: Discussionmentioning

confidence: 99%

RNA synthesis in the ultrastructural and biochemical components of the nucleolus of Chinese hamster ovary cells.

Royal¹,

Simard²

1975

The Journal of Cell Biology

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A correlated autoradiographic and biochemical study of RNA synthesis in the nucleoli of chinese hamster ovary cells has been made. Quantitative analysis of the labeling indicates that the fibrillar ribonucleoprotein (RNP) component is labeled faster than 80S RNP and 45S RNA molecules, but approaches simultaneously a steady-state 3H to 1,C ratio or grains/,m 2 after 30 min of [SH]uridine incorporation. On the other hand, the 55S RNP, the 36S + 32S RNA, and the granular RNP components have the same kinetic of labeling with [aH]uridine. These resuits suggest that the fibrillar and granular RNP components of the nucleolus are the ultrastructural substratum of, respectively, the 80S RNP (45S RNA) and 55S RNP (36S + 32S RNA). The possibility that precursors to 80S RNP exist also in the fibrillar region of the nucleolus is strongly suggested by the rapid labeling of the fibrils on the autoradiographs.It is generally admitted that the synthesis and assembly of mammalian ribosomes take place in the nucleolus (15). Biochemical studies have shown that ribosomal RNA pi'ecursors exist in the nucleolus as ribonucleoproteins (RNP) which are direct precursors of cytoplasmic ribosomal subparticles (8,20,22). These RNP particles can be visualized by electron microscopy in the form of fibrils and granules which are sensitive to pronase and ribonuclease (9) and can be labeled selectively with [SH]uridine (6).Essentially, two different RNP particles have been described in isolated nucleoli: an 80S RNP containing the 45S RNA, and a 55S RNP containing the 32S RNA (20). A rapidly labeled low molecular weight population of RNP has also been reported (2).Since pulse-chase experiments have suggested a precursor-product relationship between the fibrillar and the granular ultrastructural components (5), it has been proposed that newly synthesized preribosomal RNA first appears in the nucleolar fibrils as a low molecular weight RNP, eventually to be completed and associated with more proteins to form the 80S RNP particles (2). The nucleolar granular component could then be the ultrastructural substratum of both 80S and 55S RNP particles or only the latter. In order to assign an ultrastructural compartment to each RNP and RNA molecule in the nucleolus, we compared the incorporation of RNA precursors in both the ultrastructural and biochemical subfractions of the nucleolus. The kinetics of incorporation of [SH]uridine in the fibrillar component is grossly similar to that of the 80S RNP and 45S RNA molecules, although there

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“…The operation of post-transcriptional controls within the nucleus was suggested by the observation that a significant portion of the RNA transcribed within the nucleus never reaches the cytoplasm of the normal eukaryotic cell (Aronson & Wilt, 1969;Harris, 1970;Cooper &Gibson, 1971; . These, as yet unidentified, controls appear to be modified in the transformed cell (Shearer & Smuckler, 1972).…”

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confidence: 99%

Modified messenger ribonucleic acid release from isolated hepatic nuclei after inhibition of polyadenylate formation

Schumm

Webb

1974

Biochemical Journal

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Treatment of rats with Cordycepin (3'-deoxyadenosine), an inhibitor of nuclear poly(A) synthesis, selectively decreased the energy and cytosol-dependent release of a portion of the mRNA species from the isolated hepatic nuclei in a cell-free system by approximately 40%. An analysis of the differential binding of the transported mRNA containing poly(A) tracts to nitrocellulose filters, and to cellulose or poly(U)-Sepharose columns suggested that the poly(A) tracts in the mRNA transported from the isolated hepatic nuclei of Cordycepin-treated rats, are decreased in size. This size decrease was confirmed through an analysis of the average size of the poly(A) tracts, released from the messengers by ribonuclease activity, on sucrose density gradients.

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Control of Synthesis and Wastage of Ribosomal Ribonucleic Acid in Lymphocytes

Cited by 71 publications

References 23 publications

Biochemical characterization of RNA and protein synthesis in erythrocyte development.

Biochemical characterization of RNA and protein synthesis in erythrocyte development.

RNA synthesis in the ultrastructural and biochemical components of the nucleolus of Chinese hamster ovary cells.

Modified messenger ribonucleic acid release from isolated hepatic nuclei after inhibition of polyadenylate formation

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