Messenger ribonucleoprotein

Singh, O.P., Bjorkroth, B., Masich, S., Wieslander, L. and Daneholt, B. (1999) The intranuclear movement of Balbiani ring pre-messenger ribonucleoprotein particle. Exp. Cell Res., 251, 135-146. 

Fig. 15. Polysomal mRNP from reticulocytes. A. Sucrose gradient sedimentation of the polyribosomal suspension after EDTA treatment (40 hours centrifugation). B.Sucrose gradient sedimentation of unlabeled, sodium dodecyl sulfate-extracted polyribosomal RNA supplemented with the high specific radioactivity RNA detached from labeled polyribosomes by EDTA treatment. C. CsCi equilibrium sedimentation of the messenger ribonucleoprotein complex. Ribosomal subparticles have been added as Internal markers. The centrifugation was carried out at 4°C for 18 hours at 36,000 rpm in an SW-39 rotor. (From Huez et al. 1967. Biochim. Biophys. Acta, 145 629-636 Burny et al. 1969. Biochim, Biophys. Acta, 190 228-231.)...

Burny, A., G. Huez, G. Marbaix, and H. Chantrenne. 1969. On a messenger ribonucleoprotein complex from rabbit reticulocytes. Biochim. Biophys. Acta, 190 228-231. 

Weisberger, A. S., and S. A. Armentrout. 1966. Directed protein synthesis by messenger ribonucleoprotein and ribosomes from different mammalian species. Proc. Nat. Acad. Sci. U.S.A., 56 1612-1618. 

Nonribosomal RNA appears in the cytoplasm in the form of ribonu-cleoprotein particles called informosomes (Spirin et ah, 1964 Spirin, 1969). Such ribonucleoprotein particles, which are mostly not bound to ribosomal subunits, have been found in a variety of tissues. They are in part incorporated into polyribosomes (see Lebleu et ah, 1971 Knochel and Tiedemann, 1972 Bonanou-Tzedaki et ah, 1972). The appearance of messenger-ribonucleoprotein complexes in the polysomes is a slow process as compared to the synthesis of nuclear RNA. In chick embryos newly synthesized messenger (nonribosomal) RNA is detectable in polyribosomes after about 30 minutes. The time sequence of incorporation of mRNA into polyribosomes does not change when the RNA synthesis is completely blocked after 15 minutes by actinomycin D (Knochel, 1972b). In HeLa cells mRNA appears in the polysomes after a 15-20 minutes lag phase (Penman et ah, 1968). 

Elkaim R, Thomassin H, Niedergang C, Egly JM, Kempf J, Mandel P (1983) Adenosine diphosphate ribosyltransferase and protein acceptors associated with cytoplasmic free messenger ribonucleoprotein particles. Biochimie 65 653-659... 

Recently, we have demonstrated the existence of a poly(ADPR) polymerase activity associated with cytoplasmic free messenger ribonucleoprotein particles (mRNP) isolated from mouse plasmacytoma cells [4]. The enzyme does not require DNA for activity and is able to produce an ADP-ribosylation of some of the mRNP proteins. We have extended our observations to Krebs II ascites-tumor cells and to rat liver. In the present report, we will discuss some properties of this enzyme, particularly the activation by RNase A. 

Egly JM, Schmitt M, Elkaim R, Kempf J (1981) Protein kinases and their protein substrates in free messenger ribonucleoprotein particles and polysomes from mouse plasmacytoma cells. Eur J Biochem 118 379-387... 

Poly(ADP-ribosyl)ation is generally described as a nuclear event. However, extranuclear poly(ADP-ribose) polymerase activities have been detected in the cytosol of baby hamster kidney ceUs (1), the ribosomal fraction of HeLa cells (2) and rat testis (3). The activities looked like the nuclear enzyme in diat they totally or partially depended on DNA. We have previously reported the association of a poly(ADP-ribose) polymerase with a specific ribonucleoprotein complex, namely free messenger ribonucleoprotein particles (free mRNP) (4-6). The enzyme has the particularity to be DNA-independent. In diis paper, we have b n interested in the proteins which are poly(ADP-ribosyl)ated in free mRNP. We also present evidence of the existence of a poly(ADP-ribose) glycohydrolase in free mRNP. 

Throughout the ribosome cycle, dynamic protein-mRNA interactions are functionally important in the initiation, elongation, and termination of polypeptide synthesis. In addition, more stable associations between proteins and mRNAs have been observed, particularly in eukaryotic cells. These messenger ribonucleoprotein complexes (mRNPs) occur both in polyribosomes and free in the cytosol, some of the latter being either temporarily or permanently unavailable for translation. Thus, protein-mRNA interactions contribute to the efficiency with which mRNAs are translated. 

In the cell, messenger RNA does not exist as free molecules, but appears to be complexed with protein in messenger ribonucleoprotein... 

Hershey, J. W. B., 1982, Messenger ribonucleoprotein particles, in Protein Biosynthesis in Eukaryotes (R. Perez-Bercoff, ed.), pp. 157-166, Plenum Publishing, New York. 

Spohr, G., Granboulan, N., Morel, C., and Scherrer, K., 1970, Messenger RNA in HeLa cells An investigation of free and polyribosome-bound cytoplasmic messenger ribonucleoprotein particles by kinetic labelling and electron microscopy, Eur. J. Biochem. 17 296. 

Jones, C., and Ehrenfeld, E., 1983, The effect of poliovirus infection on the translation in vitro of VSV messenger ribonucleoprotein particles. Virology 129 415. 

Bolton et al. (1982) have also performed P-NMR experiments with messenger ribonucleoprotein (mRNP), which is about the same size as ribosomes. The T, NOE, T, R, and lP,/2 values are Usted in Table IV. The P r, value of mRNP is much smaller than that of any other nucleic acid-protein complex in Table IV in fact, it is smaller than one could expect for a P nucleus relaxed solely by protons on the RNA. Consequently, selective P( H NOE experiments were carried out in which the 3 P resonance intensity was monitored, as 50-Hz windows in the H-NMR spectrum were strongly irradiated rather than irradiating all proton frequencies, as is usually done with heteronuclear NOE experiments. The selective NOE experiments showed that the phosphorus in the mRNP was dipolar-coupled to protein protons as well as ribose protons. Apparently, the nature of the protein-nucleic add interactions differ in comparison with the other nucleic add-protdn complexes of Table IV, in that protons from the protein are much closer to the phosphorus of RNA. 

Iwaki A et al (2013) Vanillin inhibits translation and induces messenger ribonucleoprotein (mRNP) granule formation in Saccharomyces cerevisiae application and validation of high-content, image-based profiling. PLoS One 8 e61748... 

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