Enhancement of +1 Frameshift by Polyamines during Translation of Polypeptide Release Factor 2 in Escherichia coli

Polypeptide release factor 2 (RF2) in Escherichia coli is known to be synthesized by a +1 frameshift at the 26th UGA codon of RF2 mRNA. Polyamines were found to stimulate the +1 frameshift of RF2 synthesis, an effect that was reduced by excess RF2. Polyamine stimulation of +1 frameshift of RF2 synthesis was observed at the early logarithmic phase, which is the important phase in determination of the overall rate of cell growth. A Shine-Dalgarno-like sequence was necessary for an efficient +1 frameshift of RF2 synthesis, but not for polyamine stimulation. Spectinomycin, tetracycline, streptomycin, and neomycin reduced polyamine stimulation of the +1 frameshift of RF2 synthesis. The results suggest that a structural change of the A site on 30 S ribosomal subunits is important for polyamine stimulation of the +1 frameshift. The level of mRNAs of ribosomal proteins and elongation factors having UAA as termination codon was enhanced by polyamines, and OppA synthesis from OppA mRNA having UAA as termination codon was more enhanced by polyamines than that from OppA mRNA having a UGA termination codon. Furthermore, synthesis of ribosomal protein L20 and elongation factor G from the mRNAs having a UAA termination codon was enhanced by polyamines at the level of translation and transcription. The results suggest that some protein synthesis from mRNAs having a UAA termination codon is enhanced at the level of translation through polyamine stimulation of +1 frameshift of RF2 synthesis. It is concluded that prfB encoding RF2 is a new member of the polyamine modulon. Polypeptide release factor 2 (RF2) in Escherichia coli is known to be synthesized by a +1 frameshift at the 26th UGA codon of RF2 mRNA. Polyamines were found to stimulate the +1 frameshift of RF2 synthesis, an effect that was reduced by excess RF2. Polyamine stimulation of +1 frameshift of RF2 synthesis was observed at the early logarithmic phase, which is the important phase in determination of the overall rate of cell growth. A Shine-Dalgarno-like sequence was necessary for an efficient +1 frameshift of RF2 synthesis, but not for polyamine stimulation. Spectinomycin, tetracycline, streptomycin, and neomycin reduced polyamine stimulation of the +1 frameshift of RF2 synthesis. The results suggest that a structural change of the A site on 30 S ribosomal subunits is important for polyamine stimulation of the +1 frameshift. The level of mRNAs of ribosomal proteins and elongation factors having UAA as termination codon was enhanced by polyamines, and OppA synthesis from OppA mRNA having UAA as termination codon was more enhanced by polyamines than that from OppA mRNA having a UGA termination codon. Furthermore, synthesis of ribosomal protein L20 and elongation factor G from the mRNAs having a UAA termination codon was enhanced by polyamines at the level of translation and transcription. The results suggest that some protein synthesis from mRNAs having a UAA termination codon is enhanced at the level of translation through polyamine stimulation of +1 frameshift of RF2 synthesis. It is concluded that prfB encoding RF2 is a new member of the polyamine modulon. Polyamines (putrescine, spermidine, and spermine), aliphatic cations present in almost all living organisms, are necessary for normal cell growth (1Tabor C.W. Tabor H. Annu. Rev. Biochem. 1984; 53: 749-790Crossref PubMed Scopus (3228) Google Scholar, 2Cohen S.S. A Guide to the Polyamines. Oxford University Press, Oxford1998Google Scholar, 3Igarashi K. Kashiwagi K. Biochem. Biophys. Res. Commun. 2000; 271: 559-564Crossref PubMed Scopus (721) Google Scholar). Because polyamines interact with nucleic acids and mostly exist as polyamine-RNA complexes in cells (4Watanabe S. Kusama-Eguchi K. Kobayashi H. Igarashi K. J. Biol. Chem. 1991; 266: 20803-20809Abstract Full Text PDF PubMed Google Scholar, 5Miyamoto S. Kashiwagi K. Ito K. Watanabe S. Igarashi K. Arch. Biochem. Biophys. 1993; 300: 63-68Crossref PubMed Scopus (105) Google Scholar), their proliferative effects are presumed to be caused by stimulation of nucleic acid and protein synthesis. In this context, it has been reported that polyamines stimulate the synthesis of some proteins in vitro and in vivo (6Igarashi K. Sugawara K. Izumi I. Nagayama C. Hirose S. Eur. J. Biochem. 1974; 48: 495-502Crossref PubMed Scopus (122) Google Scholar, 7Atkins J.F. Lewis J.B. Anderson C.W. Gesteland R.F. J. Biol. Chem. 1975; 250: 5688-5695Abstract Full Text PDF PubMed Google Scholar, 8Igarashi K. Morris D.R. Cancer Res. 1984; 44: 5332-5337PubMed Google Scholar, 9Ito K. Kashiwagi K. Watanabe S. Kameji T. Hayashi S. Igarashi K. J. Biol. Chem. 1990; 265: 13036-13041Abstract Full Text PDF PubMed Google Scholar), increase the fidelity of protein synthesis (10Igarashi K. Kashiwagi K. Aoki R. Kojima M. Hirose S. Biochem. Biophys. Res. Commun. 1979; 91: 440-448Crossref PubMed Scopus (37) Google Scholar, 11Jelenc P.C. Kurland C.G. Proc. Natl. Acad. Sci. U. S. A. 1979; 76: 3174-3178Crossref PubMed Scopus (267) Google Scholar, 12Ito K. Igarashi K. Eur. J. Biochem. 1986; 156: 505-510Crossref PubMed Scopus (19) Google Scholar), and induce the in vivo assembly of 30 S ribosomal subunits (13Echandi G. Algranati I.D. Biochem. Biophys. Res. Commun. 1975; 67: 1185-1191Crossref PubMed Scopus (48) Google Scholar, 14Igarashi K. Kashiwagi K. Kishida K. Watanabe Y. Kogo A. Hirose S. Eur. J. Biochem. 1979; 93: 345-353Crossref PubMed Scopus (56) Google Scholar, 15Kakegawa T. Hirose S. Kashiwagi K. Igarashi K. Eur. J. Biochem. 1986; 158: 265-269Crossref PubMed Scopus (28) Google Scholar), together suggesting that polyamines regulate protein synthesis at several different steps. We have previously studied whether the translation of a defined set of proteins is enhanced by polyamines using Escherichia coli MA261, a polyamine-requiring mutant. The strain MA261 is unable to synthesize putrescine, and cell growth slows down in the absence of exogenous putrescine (16Cunningham-Rundles S. Maas W.K. J. Bacteriol. 1975; 124: 791-799Crossref PubMed Google Scholar). When putrescine is added to the culture medium, it is taken up into cells, and spermidine is synthesized from putrescine, leading to the recovery of cell growth. By comparing the protein expression pattern in MA261 cultured with or without putrescine, we reported previously that polyamines increase the synthesis of several proteins at the level of translation (17Igarashi K. Saisho T. Yuguchi M. Kashiwagi K. J. Biol. Chem. 1997; 272: 4058-4064Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar, 18Yoshida M. Kashiwagi K. Kawai G. Ishihama A. Igarashi K. J. Biol. Chem. 2001; 276: 16289-16295Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 19Yoshida M. Kashiwagi K. Kawai G. Ishihama A. Igarashi K. J. Biol. Chem. 2002; 277: 37139-37146Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar, 20Yoshida M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar). These include OppA (17Igarashi K. Saisho T. Yuguchi M. Kashiwagi K. J. Biol. Chem. 1997; 272: 4058-4064Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar), a periplasmic substrate-binding protein of the oligopeptide uptake system; adenylate cyclase (18Yoshida M. Kashiwagi K. Kawai G. Ishihama A. Igarashi K. J. Biol. Chem. 2001; 276: 16289-16295Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar); RpoS (σ38) (19Yoshida M. Kashiwagi K. Kawai G. Ishihama A. Igarashi K. J. Biol. Chem. 2002; 277: 37139-37146Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar), one of the subunits of factor M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar), a factor for the and M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar), a of of some for and some We that the expression is enhanced by polyamines at the level of translation be as a In the of RpoS (σ38) synthesis, to at the of release factor elongation factor G. release factor elongation factor G. of mRNA was enhanced by polyamines (19Yoshida M. Kashiwagi K. Kawai G. Ishihama A. Igarashi K. J. Biol. Chem. 2002; 277: 37139-37146Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar). The termination codon in the of mRNA be not by but by +1 frameshift. In cells, it has been reported that mRNA has the termination codon UGA at the of and the +1 frameshift is enhanced by polyamines T. S. Y. Hayashi S. Biophys. PubMed Scopus Google Scholar, S. T. Y. Y. J.F. Gesteland R.F. Hayashi S. Full Text PDF PubMed Scopus Google Scholar). is in the of polyamine in cells by the of and by the polyamine uptake Y. S. Y. Hayashi S. J. Biol. Chem. Full Text PDF PubMed Google Scholar, Y. S. Kameji T. Hayashi S. Igarashi K. T. K. A. PubMed Scopus Google Scholar, T. Y. Kashiwagi K. Y. Hayashi S. Igarashi K. Proc. Natl. Acad. Sci. U. S. A. 91: PubMed Scopus Google Scholar, A. Biochem. J. PubMed Scopus Google Scholar). In release factor 2 which UGA and UAA as termination is known to be synthesized by a +1 frameshift at the 26th UGA termination codon of RF2 mRNA Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, 1986; PubMed Scopus Google Scholar). In this we whether the +1 frameshift of RF2 mRNA is enhanced by and coli Morris D.R. Biochem. Biophys. Res. Commun. PubMed Scopus Google and MA261 (16Cunningham-Rundles S. Maas W.K. J. Bacteriol. 1975; 124: 791-799Crossref PubMed Google were by R. Morris of and by K. Maas University of growth of A of of of of of of of 2 of of and and of and of and of of was was by the of of to the growth of MA261, of of of of of of 2 of of of and of was The cells were cultured in the absence or of putrescine growth was by the at to proteins by to protein C. PubMed Scopus Google was by S. of from coli was to the of R. K. in Scholar). the was using as and and as the was using as and and as The prfB and a and is defined as the A in the codon were with and and into the of to and of and and were using and as and and as with the was into the of by using PubMed Scopus Google was to and the was using as and and for UGA with and and as The was using the as and and as and was using the with the was into the site of in which the is the of were of was using as and and as with the was into the site of and was using and as and and as with the were into the site of in which prfB or the is the of were The encoding having UGA as termination codon was from having UAA as termination codon in 14Igarashi K. Kashiwagi K. Kishida K. Watanabe Y. Kogo A. Hirose S. Eur. J. Biochem. 1979; 93: 345-353Crossref PubMed Scopus (56) Google with by using PubMed Scopus Google Scholar). The sequence of the was by the was by the of H. J. G. J. Biol. Chem. Full Text PDF PubMed Google using RF2 K. M. Y. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google was by Y. University of and that protein was from ribosomal protein L20 and elongation factor G were as previously K. Y. Igarashi K. Arch. Biochem. Biophys. PubMed Scopus Google Scholar, G. H. Igarashi K. A. PubMed Scopus Google Scholar). The level of protein was by a and was from coli MA261 and cells to the of and J. Bacteriol. 1990; PubMed Google Scholar). was using of and the J. T. J. A Scholar). of prfB was using and and was with using a and as was as previously M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google with from coli MA261 cultured in the and absence of putrescine and at using coli In RF2 protein was by Y. K. M. Y. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). G. Annu. Rev. PubMed Scopus Google were using an coli for the with A of of of acids without of of the and and spermidine at the the was as it the of and spermidine was and the effect of RF2 protein and on spermidine stimulation of the +1 frameshift of RF2 synthesis, the of RF2 and in the were added to the at for 2 of and of acid were added to the of the was with of for PubMed Scopus Google and for 2 A was for and was to the of and Eur. J. Biochem. 1975; PubMed Scopus Google Scholar). of proteins was using a of to 30 S through of from coli and 30 S ribosomal subunits from were as previously K. Kishida K. Kashiwagi K. I. T. Hirose S. Eur. J. Biochem. PubMed Scopus Google Scholar, Y. Igarashi K. Hirose S. Biophys. PubMed Scopus Google Scholar). The for spermidine to 30 S ribosomal subunits of 30 S ribosomal and at the at 30 for 30 an of and was added to the the was at 30 for 30 proteins were with acid and 30 T. Hirose S. Igarashi K. Arch. Biochem. Biophys. 1986; PubMed Scopus Google Scholar). The by at for was with of The was in the and proteins were by the was in an and the was in the of Proc. Natl. Acad. Sci. U. S. A. 67: PubMed Scopus Google Scholar). of the proteins was to the by and Proc. Natl. Acad. Sci. U. S. A. 67: PubMed Scopus Google Scholar). The into of the ribosomal protein was using a of Polyamines on in +1 of RF2 is known that synthesis a +1 frameshift at the termination codon of of mRNA in cells, and the of this frameshift is enhanced by polyamines T. S. Y. Hayashi S. Biophys. PubMed Scopus Google Scholar, S. T. Y. Y. J.F. Gesteland R.F. Hayashi S. Full Text PDF PubMed Scopus Google Scholar). Because RF2 in coli is synthesized by a +1 frameshift at the 26th termination codon Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, 1986; PubMed Scopus Google Scholar), the effect of polyamines on the of this frameshift was using the polyamine-requiring MA261 and When were cultured in the of putrescine, polyamines and in cells and cell growth not The level of RF2 was by polyamines at the early logarithmic phase which is the important phase with the to the overall rate of cell growth. The level of RF2 with the of cell growth and the effect of polyamines The level of RF2 mRNA was in cells cultured with or without putrescine a the level of one of the subunits of was and it was not by polyamine not The results suggest that the +1 frameshift of RF2 synthesis is enhanced by polyamines and by RF2 1986; PubMed Scopus Google Scholar). The effects of polyamines were using J. PubMed Scopus Google Scholar). In this of be by a +1 frameshift a and a termination of the +1 frameshift was as the of the level of +1 frameshift by the level of in the +1 frameshift of RF2 was enhanced by polyamines The polyamine effect was in this of the of level of mRNA synthesized from the The results that the +1 frameshift of RF2 synthesis is enhanced by that polyamine of +1 frameshift were using coli The termination codon at the 26th codon of of RF2 mRNA was to termination and or to for polyamine of the +1 frameshift was not by this codon The of a sequence at the of the termination codon was the sequence was polyamine of the +1 frameshift was observed of the sequence and When the sequence was to a sequence the +1 frameshift and it to be whether polyamines are in the the sequence and S of and on in +1 of RF2 in vitro protein G. Annu. Rev. PubMed Scopus Google was to the factors the +1 frameshift of RF2 synthesis. in RF2 synthesis was enhanced by spermidine, but not enhanced the +1 frameshift of RF2 synthesis in a and The effect of RF2 on the +1 frameshift of RF2 synthesis was in and the of RF2 reduced +1 frameshift of RF2 synthesis and reduced the polyamine of this frameshift. Because it was not in an in vivo whether polyamines at the level of the the sequence and S this was in an in vitro When the sequence was the of the +1 frameshift polyamine of the frameshift was observed The results suggest that polyamines on 30 S ribosomal subunits than on RF2 mRNA. We whether synthesis was enhanced by polyamines in an in vitro coli mRNA not have the sequence S. T. Y. Y. J.F. Gesteland R.F. Hayashi S. Full Text PDF PubMed Scopus Google and of +1 frameshift was spermidine enhanced +1 frameshift of synthesis not suggesting that polyamines on 30 S ribosomal of on Polyamine of in +1 of RF2 was using an in vitro in polyamine stimulation of the +1 frameshift of RF2 was by the of streptomycin, tetracycline, and which at the A site of 30 S ribosomal subunits 2000; PubMed Scopus Google Scholar, S. J. PubMed Scopus Google Scholar, 2000; Full Text Full Text PDF PubMed Scopus Google Scholar), in with the in protein synthesis polyamine stimulation of was not by and which at the or site of 30 S ribosomal subunits 2000; Full Text Full Text PDF PubMed Scopus Google Scholar, M. J. R. M. H. A. H. T. C. T. A. J. 2001; PubMed Scopus Google Scholar), protein and The results suggest that structural change at the A site of 30 S ribosomal subunits by polyamines is important for polyamine stimulation of the +1 frameshift of RF2 synthesis. Polyamine stimulation of the +1 frameshift of RF2 was more by and than by and neomycin It has been reported that and to the A site 2000; PubMed Scopus Google Scholar, S. J. PubMed Scopus Google Scholar, 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). proteins and are to the A site C. T. 2000; PubMed Scopus Google Scholar, A. K. 2001; PubMed Scopus Google Scholar). the level of spermidine to the A site of 30 S ribosomal subunits was in the and absence of through spermidine to 30 S ribosomal proteins by T. Hirose S. Igarashi K. Arch. Biochem. Biophys. 1986; PubMed Scopus Google Scholar). in spermidine to was in the of we not the spermidine level to spermidine to was results were with not the of growth of a polyamine by and was reduced by polyamines not These results that the level of spermidine to the A site of 30 S ribosomal subunits in the of and and it is that the in polyamine stimulation of the +1 frameshift of RF2 synthesis by is to a in spermidine to the A site of 30 S ribosomal of mRNA by Polyamines at the were to the of the stimulation of +1 frameshift of RF2 synthesis at the early logarithmic In mRNAs that are by polyamines were by It has been reported that of the termination codon UAA by RF2 is than that of UGA J. M. J. Biol. PubMed Scopus Google Scholar). the early logarithmic phase, expression of was enhanced by polyamines more than at In expression of the in the of and translation were enhanced by polyamines Because expression of in translation as ribosomal proteins and elongation factors of protein synthesis was not enhanced by polyamines at the logarithmic phase M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar), the of UAA as a termination codon was in the mRNAs in in the of UAA as a termination codon the mRNAs at the early logarithmic phase was and that the mRNAs by polyamines was the of UAA as a termination codon the mRNAs in translation was and that in the mRNAs by polyamines was it was whether protein synthesis from mRNA having UAA as termination codon at the early logarithmic phase be enhanced by polyamines at the level of the increase in RF2 using OppA mRNA synthesis is enhanced by polyamines (17Igarashi K. Saisho T. Yuguchi M. Kashiwagi K. J. Biol. Chem. 1997; 272: 4058-4064Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar). in synthesis of OppA from the mRNA having UAA as termination codon was more enhanced by polyamines at the level of translation than that from the mRNA having UGA as termination codon. The level of OppA mRNAs was enhanced by polyamines by These results suggest that the mRNAs having UAA as a termination codon were more through termination of the synthesis of of ribosomal protein L20 and from the mRNAs having UAA termination codon was enhanced by polyamines at the level of not but the level of mRNAs was enhanced by polyamines and the level of the proteins was enhanced by polyamines a synthesis of of from the mRNA having a UGA termination codon was The level of protein and mRNA was enhanced by polyamines not synthesis of the protein was not enhanced by polyamines at the level of of polyamines on OppA synthesis from the mRNA having UAA or UGA as termination codon and on synthesis of ribosomal protein L20 and coli MA261 with or was cultured in When the cells were into and in the and absence of putrescine for was added to and the cells were to for of OppA synthesis by was as previously (17Igarashi K. Saisho T. Yuguchi M. Kashiwagi K. J. Biol. Chem. 1997; 272: 4058-4064Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar). of OppA mRNA was as using the in K. Saisho T. Yuguchi M. Kashiwagi K. J. Biol. Chem. 1997; 272: 4058-4064Abstract Full Text Full Text PDF PubMed Scopus (46) Google the level of mRNA and protein of ribosomal protein L20 and was by and The were and the was of Polyamines on of one more protein is synthesized by the that the of is synthesized by the frameshift of mRNA A. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar). The effect of polyamines on frameshift of mRNA was using in vivo and in vitro in of the frameshift in vivo is in the absence of polyamines in MA261 and and polyamines not the frameshift of mRNA in vivo and in results that the +1 frameshift of RF2 synthesis in coli was enhanced by this was observed at the early logarithmic phase of cell synthesis of RF2 is by RF2 protein 1986; PubMed Scopus Google Scholar), and the level of RF2 was with the of cell growth. It is known that polyamines the +1 frameshift of synthesis in cells S. T. Y. Y. J.F. Gesteland R.F. Hayashi S. Full Text PDF PubMed Scopus Google and R. H. K. J. 2004; PubMed Scopus Google Scholar). Polyamine of the +1 frameshift in synthesis of RF2 and When the level of RF2 is at the early logarithmic phase, polyamines stimulate RF2 synthesis to release the protein from When of polyamines to cells, is to the level of polyamines in is known to stimulate of a in polyamine Y. S. Y. Hayashi S. J. Biol. Chem. Full Text PDF PubMed Google Scholar, Y. S. Kameji T. Hayashi S. Igarashi K. T. K. A. PubMed Scopus Google Scholar), and to polyamine uptake T. Y. Kashiwagi K. Y. Hayashi S. Igarashi K. Proc. Natl. Acad. Sci. U. S. A. 91: PubMed Scopus Google Scholar, A. Biochem. J. PubMed Scopus Google Scholar). It be that the +1 frameshift at codon of protein for of in is by polyamines Tabor C.W. Tabor H. Proc. Natl. Acad. Sci. U. S. A. 91: PubMed Scopus Google Scholar). to the synthesis of of and protein of the in Tabor C.W. Tabor H. Proc. Natl. Acad. Sci. U. S. A. 91: PubMed Scopus Google is not by The results suggest that the of +1 and on is the +1 frameshift in RF2 synthesis, an sequence was necessary to down the of an sequence not polyamine stimulation of the +1 frameshift. we that polyamines on than mRNA to stimulate +1 and tetracycline, which to the A site of 30 S ribosomal subunits 2000; PubMed Scopus Google Scholar, S. J. PubMed Scopus Google Scholar, 2000; Full Text Full Text PDF PubMed Scopus Google Scholar), reduced the polyamine of +1 and which to the site with an sequence of RF2 mRNA on 30 S ribosomal not the +1 The results suggest that spermidine to and a structural change in the A site to the +1 frameshift. It has been reported that release of the site from the is with level 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). results suggest that polyamines not stimulate release of the site and which at the or site of 30 S ribosomal not polyamine stimulation of the +1 frameshift of RF2 synthesis. Polyamines to (4Watanabe S. Kusama-Eguchi K. Kobayashi H. Igarashi K. J. Biol. Chem. 1991; 266: 20803-20809Abstract Full Text PDF PubMed Google Scholar, K. Aoki Y. Hirose S. J. Biochem. PubMed Scopus Google Scholar). We have that the of a to sequence of OppA mRNA is important for spermidine stimulation of to M. Kashiwagi K. Kawai G. Igarashi K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). It is that of in with polyamines in cells (4Watanabe S. Kusama-Eguchi K. Kobayashi H. Igarashi K. J. Biol. Chem. 1991; 266: 20803-20809Abstract Full Text PDF PubMed Google Scholar, 5Miyamoto S. Kashiwagi K. Ito K. Watanabe S. Igarashi K. Arch. Biochem. Biophys. 1993; 300: 63-68Crossref PubMed Scopus (105) Google Scholar), and the site of polyamines on S has been I. Res. 2002; PubMed Scopus Google Scholar). of polyamines and of at the A site of 30 S ribosomal subunits were to and the of spermidine at the A site was by from the in spermidine to results suggest that spermidine to the A site is important for spermidine stimulation of +1 frameshift RF2 synthesis. Because RF2 to the A site J. M. J. M. J. PubMed Scopus Google Scholar), the of RF2 the +1 frameshift by with spermidine to the A These taken suggest that a structural change of the site by polyamines is important for the +1 frameshift of RF2 synthesis, and on the A site and RF2 the polyamine stimulation of the +1 frameshift through their to the It is that expression of mRNAs encoding ribosomal proteins and elongation factors was enhanced by polyamines at the early logarithmic Because mRNAs the UAA termination it is that the of translation from mRNAs is by polyamine of RF2 synthesis from the results of OppA synthesis and polyamine of the synthesis of ribosomal protein L20 and at the of and translation in The of polyamine stimulation of the synthesis of mRNAs is It is known that polyamines stimulate cell growth through of the assembly of 30 S ribosomal subunits (13Echandi G. Algranati I.D. Biochem. Biophys. Res. Commun. 1975; 67: 1185-1191Crossref PubMed Scopus (48) Google Scholar, 14Igarashi K. Kashiwagi K. Kishida K. Watanabe Y. Kogo A. Hirose S. Eur. J. Biochem. 1979; 93: 345-353Crossref PubMed Scopus (56) Google Scholar, 15Kakegawa T. Hirose S. Kashiwagi K. Igarashi K. Eur. J. Biochem. 1986; 158: 265-269Crossref PubMed Scopus (28) Google and stimulation of the synthesis of of proteins that are important for cell growth M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar, K. Kashiwagi K. J. Biochem. PubMed Scopus (122) Google Scholar). We that the expression is enhanced by polyamines at the level of translation are as polyamine modulon. are and M. Kashiwagi K. Shigemasa A. Taniguchi S. Yamamoto K. Makinoshima H. Ishihama A. Igarashi K. J. Biol. Chem. 2004; 279: 46008-46013Abstract Full Text Full Text PDF PubMed Scopus (121) Google Scholar). expression of mRNAs by the factors are enhanced by We found that expression of mRNAs is enhanced by at polyamine of expression of mRNAs was not by the are in to a new polyamine from the encoding factors a factor for ribosomal protein present results that prfB encoding RF2 is a new member of polyamine RF2 is not a is known to the synthesis of ribosomal J. Bacteriol. 2001; PubMed Scopus Google Scholar). of the synthesis of ribosomal proteins by polyamines, of the of RF2 synthesis, at the early logarithmic phase is important for efficient protein synthesis through We K. for in the are to Y. K. S. S. K. and R. Morris for the of RF2 and coli with