Subribosomal particles and the transport of messenger RNA in HeLa cells

McConkey, Edwin H.; Hopkins, J. W.

doi:10.1016/s0022-2836(65)80245-5

Cited by 142 publications

(19 citation statements)

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“…These results would be coincided with the evidence for RNA transport from nucleus to the cytoplasm in mammalian cells (17)(18)(19). The specific activity of nuclear, mito chondrial and supernatant RNA was enhanced by vitamin D3 administration, but that of micro somal RNA was rather depressed.…”

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confidence: 82%

Vitamin D3 Action on RNA Synthesis in Rat Intestinal Mucosa

et al. 1971

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Vitamin D3 action on uridine-5-3H incorporation into rat intestinal mucosal RNA was studied. The uridine was administered 1 hour after 2,000 iu vitamin D3 treatment.Specific activity of RNA in nuclear and supernatant fractions was increased by vitamin D3 at 15 minutes after uridine-5-3H administration. Two hours after uridine-5-3H administration, specific activity of RNA in nuclei, mitochondria and supernatant were also increased, but it was decreased in microsome.Mucosal RNA was further analyzed by methylated albumin-kieselguhr column. It was found that uridine-5-3H incorporation into sRNA was increased and that into rRNA was decreased with vitamin D3 administration.DNA dependent RNA polymerase activities were studied in isolated nuclei obtained from rat intestinal mucosal cell. Mg2+-activated DNA dependent RNA polymerise was not influenced at 1 hour after vitamin D3 administration, however, decreased at 3 hours and 16 hours after vitamin D3 treatment. These decreases of activity would be corresponded with decreases of uridine-5-3H incorporation into rRNA. Mn2+ and (NH4)2S04-activated DNA dependent RNA polymerase was not influenced by vitamin D3.Many workers have already shown the essential role of vitamin D (calciferol) in mediating the absorption of calcium from the small intestine.It has required some lag period to appear the physiological response of the enhanced calcium absorption after the ad ministration of vitamin D3 (1). The hypothesis was proposed that vitamin D3-mediated enhance ment of intestinal calcium transport is achieved indirectly through RNA and protein synthesis. This hypothesis was primarily based on the finding that actinomycin D inhibits the intestinal response to vitamin D (2, 3). In our laboratory, Moriuchi et al. have demonstrated the evidences that 3H-vitamin D3 was found inside nuclei in rat intestinal mucosa with the electronmicroscopic radioauto graphy (4). Calcium-binding protein was puri fied by Wasserman and Taylor (5) in chick intestinal mucosa and also in the rat by Moriuchi (6) and Ooizumi (7). This protein is hardly found in rachitic rat, and the presence of two kinds of the protein in vitamin D3 treated rats suggests that it may have been induced by vitamin D3 (7).In this paper, we studied on the RNA metabolism in rat intestinal mucosa cell to elucidate the primary action of vitamin D3.73

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confidence: 82%

Vitamin D3 Action on RNA Synthesis in Rat Intestinal Mucosa

et al. 1971

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“…Though evidence for a direct interaction between hormones and repressors or genes for those enzymes whose synthesis may be controlled by hormones is still to be provided, there are two important considerations, resulting from recent work mentioned below, which must now be taken into account and which necessitate a re-evaluation of some oversimplified concepts. (a) It now appears, from the work from the Laboratories of Penman, Darnell and Hiatt, that in nucleated cells m-RNA may only be transported from the nucleus to the cytoplasm as a complex with the smaller ribosomal sub-unit (Girard, Latham, Penman & Darnell, 1965;Henshaw, Revel & Hiatt, 1965;McConkey & Hopkins, 1965). The complex would then directly form polyribosomes by combining with the larger ribosomal sub-unit.…”

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confidence: 99%

“…It seems, however, that the nucleus or nucleolus does not contain any appreciable pool of finished ribosomes (Penman, Smith & Holtzman, 1966), but that these are directly assembled in the cytoplasm as polysomes from the two ribosomal sub-units (45s and 60s in mammalian cells), the smaller of the two bearing m-RNA (Girard et aZ. 1965;Henshaw et al 1965;McConkey & Hopkins, 1965). Most of the monomeric ribosomes in the cytoplasm are considered to be derived from polysomes.…”

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confidence: 99%

The formation and distribution of ribosomes during hormone-induced growth and development

Tata¹

1967

Biochemical Journal

133

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“…Nevertheless, it is thought that ribosomal subunits (53)(54)(55), and possibly other proteins (56)(57)(58)(59)(60), may be involved in the transport of messenger RNA from the nucleus to the cytoplasm. The rate of messenger RNA synthesis might be controlled by the rate at which it is removed from the template.…”

Section: Discussionmentioning

confidence: 99%

Reinitiation of RNA Synthesis on Transcription of Chromatin DNA by Escherichia coli RNA Polymerase

Morris

Gould

1971

Proc. Natl. Acad. Sci. U.S.A.

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The transcription of DNA in chromatin by Escherichia coli RNA polymerase resembles that of isolated DNA in two important respects: the release of nascent RNA and reinitiation of RNA synthesis is dependent on the salt concentration, and RNA synthesis is markedly stimulated by the addition of ribosomes.Recent experiments have established that the release of nascent RNA and reinitiation of RNA synthesis by Escherichia coli RNA polymerase with DNA templates occurs only in favorable ionic conditions (1-8). The ability of ribosomes to bind to nascent RNA (9-11) and stimulate the transcription of DNA (12)(13)(14)(15)(16)(17) in vitro is also well documented. The possibility exists that these particular factors might also govern the transcription of chromatin templates, and we show here that this is indeed the case in an in vitro system. RESULTSThe effect of variation in the KCl concentration in the assay mixture on the incorporation of labeled UTP into RNA, directed by chicken kidney chromatin, is shown in Fig. 1.The maximum rate of RNA synthesis measured in a 20-min incubation was observed at 0.25 M KCl. The optimum divalent cation concentration at 0.25 M KCl is 5-10 mM as shown in Figure 2. The rates of UTP incorporation at 0 and 0.25 M KCl are similar in the first few minutes of the incubation. Thereafter, as may be seen in Fig. 3, RNA synthesis in the absence of salt ceases, while that in the presence of salt continues for about 90 min, although at a diminishing rate. The overall stimulation of RNA synthesis in the presence of salt is generally found to be [2][3][4] fold.The following experiment shows that the stimulatory effect of KCl is accompanied by the release of nascent chains from the enzyme and the template. The synthesized RNA was fractionated by filtration on Millipore filters. Released RNA would be expected to flow through the filter, whereas RNA bound to chromatin or RNA polymerase would not (6,18,19). The results illustrated in Fig. 4 show that the RNA synthesized in the absence of salt is all retained by a Millipore filter. The excess RNA produced by the presence of salt passes through the filter.In the absence of salt, RNA polymerase cannot reinitiate RNA synthesis. This was shown with the antibiotic rifampicin, which blocks initiation but allows the synthesis of initiated chains to go to completion (6,20). Fig. 5 shows that rifampicin added 2 min after the start of incubation totally 481 represses the stimulation by KCL. The increase in RNA synthesis is thus a direct consequence of reinitiation. RNA synthesis at high, but not at low, ionic strength is further stimulated by the addition of ribosomes. At 0.25 M KCl, in the experiment shown in Fig. 6, we obtained more than a tenfold increase in RNA synthesis at the optimal ribosome concentration. Whereas the salt effect becomes increasingly more apparent as a function of incubation time, the ribosome effect is manifested early in the reaction and is relatively constant throughout the course of RNA synthesis (Fig. 7). (1, 2). Incubation was as d...

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Subribosomal particles and the transport of messenger RNA in HeLa cells

Cited by 142 publications

References 17 publications

Vitamin D3 Action on RNA Synthesis in Rat Intestinal Mucosa

Vitamin D3 Action on RNA Synthesis in Rat Intestinal Mucosa

The formation and distribution of ribosomes during hormone-induced growth and development

Reinitiation of RNA Synthesis on Transcription of Chromatin DNA by Escherichia coli RNA Polymerase

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