A test for masked message: The template activity of messenger ribonucleoprotein particles isolated from sea urchin eggs

Jenkins, Nancy A.; Kaumeyer, John F.; Young, Elihu; Raff, Rudolf A.

doi:10.1016/0012-1606(78)90134-3

Cited by 128 publications

(30 citation statements)

References 43 publications

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“…Such a mechanism operates in the conversion of stored mRNA present in nontranslated RNase-insensitive ribonucleoprotein particles to translatable RNase-sensitive mRNA after fertilization of sea urchin and mouse eggs (30,31).…”

Section: Discussionmentioning

confidence: 99%

Alternative modes of enkephalin biosynthesis regulation by reserpine and cyclic AMP in cultured chromaffin cells.

Eiden¹,

Giraud²,

Affolter³

et al. 1984

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

110

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Exposure of bovine chromaffin cells in primary culture to 5 ,.M reserpine or 25 ,uM forskolin results in an increase in enkephalin peptide levels within 24-48 hr; 25 j!M forskolin (or cholera toxin at 50 ,.g/ml) causes a 1.5-to 2-fold increase in enkephalin peptide levels, which is maximal after 48 hr of exposure and is totally blocked by addition of cycloheximide (0.5 ,Lg/ml). Reserpine (5 ,.M) elicits a 1.5-to 2-fold increase in enkephalin peptide levels within 24 hr, which is only partially blocked by cycloheximide. Chromatographic analysis of cellular extracts shows that forskolin increases levels of both [Metlenkephalin pentapeptide and high molecular weight enkephalin-containing peptides, while reserpine causes an increase in [Metlenkephalin pentapeptide and a concomitant Decrease in high molecular weight enkephalin-containing peptides, suggesting enhanced conversion of enkephalin precursor(s) to the mature polypeptide hormone. Measurement of preproenkephalin messenger RNA (mRNAe k) by RNA blot hybridization witli a cDNA probe for mRNAenk reveals that forskolin and cholera toxin cause a relatively rapid (<17 hr) 3-to 5-fold increase in mRNAenk, while exposure to reserpine elicits a gradual decrease in enkephalin mRNA (a 50%-80% decline) beginning within 24 hr and continuing over a 72-hr peritd. These results suggest that forskolin and reserpine differentially regulate enkephalin biosynthesis in cultured chromaffin cells, the former by increasing, presumably via a cAMP-dependent mechanism, cellular mRNA coding for preproenkephalin and the latter by a post-translational increase in proenkephalin processing.The parenchymal or chromaffin cells of the adrenal medulla have been long studied as a prototype of the biochemistry and cell biology of catecholamine biosynthesis and secretion in diverse neuroendocrine cell types and in neurons (1, 2). The bovine adrenal medulla also contains high levels of enkephalin peptides and has been used as starting material both for the purification and sequencing of preproenkephalin peptides and for cloning and sequencing complementary DNA to preproenkephalin messenger RNA (mRNAenk) (3)(4)(5)(6). In addition, primary cultures of bovine adrenomedullary cells have been used as a model system to examine enkephalin peptide co-release with catecholamines and the regulation of enkephalin biosynthesis by hormones and pharmacological agents (7)(8)(9)(10)(11)(12). In this study, we examined whether the effects of two types of pharmacological agents known to increase enkephalin peptide levels in chromaffin cells (9, 10, 12) could be accounted for by increased enkephalin gene transcription, which would be reflected in increased cellular mRNAenk, or if post-transcriptional events such as mRNA translation or preproenkephalin processing might be regulat- Peptide Radioimmunoassay.[Met]Enkephalin immunoreactivity in culture media and cell extracts (12) was measured by radioimmunoassay, using an enkephalin antiserum (RB-4) provided by Steve Sabol (National Heart, Lung, and Blood Institut...

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Section: Discussionmentioning

confidence: 99%

Alternative modes of enkephalin biosynthesis regulation by reserpine and cyclic AMP in cultured chromaffin cells.

Eiden¹,

Giraud²,

Affolter³

et al. 1984

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

110

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“…It has been reported that mRNP preparations from sea urchin eggs [24] and mouse ascites cells I181 can be activated by salt treatment. The untranslated mRNPs from FEL cells were also activated by exposure to salt (Fig.…”

Section: Translational Efficiency Of Eef-tu-containing Mrnp Particlesmentioning

confidence: 99%

Translational repression of mRNA for eucaryotic elongation factors in Friend erythroleukemia cells

Slobin

Jordan

1984

Eur J Biochem

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Poly(A)-containing mRNA was prepared from polyribosomes and postpolyribosomal messenger ribonucleoprotein particles (mRNP) from Friend erythroleukemic cells. Both mRNA types were translated in vitro and the 35S-labeled translation products examined by two-dimensional gel electrophoresis. Among the most abundant untranslated mRNA species was the mRNA coding for eucaryotic elongation factor Tu (eEF-Tu). In addition, the mRNA for eucaryotic elongation factor Ts was also present in Friend cells in untranslated form. Calculations based on translation assays indicate that eEF-Tu represents about 15% of the translation products of RNP mRNA and that approximately 40% of the eEF-Tu synthesized in vitro is encoded by translationally repressed mRNA. This repressed mRNA can be activated by addition of cycloheximide to cell cultures. At the level of 0.1 pg/ml, cycloheximide was found to inhibit cellular protein synthesis by about 50% while augmenting the relative rate of eEF-Tu synthesis 1.6-fold. This result suggested that eEF-Tu mRNA might initiate poorly. However, addition of supersaturating levels of mRNA to a reticulocyte lysate augmented eEF-Tu synthesis about twofold, while generally depressing the synthesis of other proteins by about 40%. Thus the storage of large amounts of eEF-Tu mRNA in vivo is unlikely to be due directly to the ineffectiveness of the mRNA in competing for the initiation machinery of the cell. The results presented in this report suggest that the supply of active eEFTu in erythroleukemic cells is controlled, at least in part, by a translational mechanism.

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“…The drug blocks the accelerated rate of protein synthesis in the 68 h post-fertilization embryo, prevents the occurrence of such qualitative protein changes as are normally detectable and blocks overt blastocyst formation Braude, 1978;and unpublished data (Young, 1977). In the sea-urchin, mRNA associated with ribonuclear protein particles (RNPs) will not translate in vitro unless the protein is first removed, and this apparent inhibitory effect of protein may represent an in-situ control mechanism (Jenkins, Kaumeyer, Young & Raff, 1978). Also in the sea-urchin, a burst of polyadenylation of pre-existent mRNA occurs at fertilization (Wilt, 1977), but the same does not appear to occur in the mouse .…”

Section: The Maternal Environmentmentioning

confidence: 99%

Intrinsic and extrinsic factors in preimplantation development

Johnson¹

1979

Reproduction

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A test for masked message: The template activity of messenger ribonucleoprotein particles isolated from sea urchin eggs

Cited by 128 publications

References 43 publications

Alternative modes of enkephalin biosynthesis regulation by reserpine and cyclic AMP in cultured chromaffin cells.

Alternative modes of enkephalin biosynthesis regulation by reserpine and cyclic AMP in cultured chromaffin cells.

Translational repression of mRNA for eucaryotic elongation factors in Friend erythroleukemia cells

Intrinsic and extrinsic factors in preimplantation development

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