Requirement for 7-methylguanosine in translation of globin mRNA in vivo

Lockard, Raymond E.; Lane, Charles D.

doi:10.1093/nar/5.9.3237

Cited by 60 publications

(26 citation statements)

References 35 publications

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“…This work shows that the in vivo structural requirements of mRNA resulting in maximal translation observed in XenoQpus oocytes also holds true for plant and animal cells. The requirement for a 5' cap observed here is similar to that found for mRNAs injected into oocytes (30,32,44). However, RNA expression in both plant and animal cultured cells shows a much greater dependence on the presence of a poly A tail than has been previously described in Xenopus oocytes (36).…”

Section: Discussionsupporting

confidence: 82%

“…We have investigated the use of another technique, electroporation, to introduce mRNAs into eukaryotic cells. Electroporation is the application of an electric field to reversibly permeabilize biomembranes (18) and has been indicated that the cap present at the 5' end of cellular and many viral mRNA molecules as a 5' to 5' 7m GpppN linkage is important both for RNA stability and translation initiation, although there are naturally occurring uncapped viral mRNAs (30)(31)(32)(33). The role of the poly adenylate residues at the 3' end (poly A tail) of mRNAs is less understood ( 34,35).…”

Section: Iniroducfionmentioning

confidence: 99%

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Expression of mRNA electroporated into plant and animal cells

Callis

Fromm

Walbot

1987

Nucleic Acids Research

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A general method to introduce RNA molecules into plant protoplasts and animal cells is described. This technique utilizes the ability of electric pulses of high field strength to form pores in biomembranes. RNA molecules containing the coding region for the bacterial enzyme chloramphenicol acetyltransferase (CAT) were used as a model system. The presence of CAT activity as a result of the in vivo translation of the introduced RNA is entirely dependent on the presence of a 5' cap and greatly increased by the presence of a poly A tail at the 3' end. The introduction of RNA into eukaryotic cells has broad applicability both as an assay for the uptake of nucleic acids into cells independent of transcriptional activity and as a tool to study eukaryotic mRNA translation. Introduction of RNA into plant protoplasts Maize and carrot protoplasts were prepared and the electroporation solutions used were as described previously (22) with the addition of an extra wash prior to electroporation. Protoplasts INIRODUCfION

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Section: Discussionsupporting

confidence: 82%

Section: Iniroducfionmentioning

confidence: 99%

Expression of mRNA electroporated into plant and animal cells

Callis

Fromm

Walbot

1987

Nucleic Acids Research

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“…The resulting decapped RNAs would likely be more susceptible to degradation by cellular nucleases, as it has been shown that the 5' cap structure stabilizes RNAs against nucleolytic degradation both in vivo and in cell extracts (12,20). Direct evidence in support of this hypothesis would be the identification in virus-infected cells of nuclear ALV and ,-actin transcripts lacking 10 (18).…”

Section: Resultsmentioning

confidence: 99%

Metabolism and expression of RNA polymerase II transcripts in influenza virus-infected cells.

Katze¹,

Krug²

1984

Mol. Cell. Biol.

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Influenza virus infection has adverse effects on the metabolism of two representative RNA polymerase II transcripts in chicken embryo fibroblasts, those coding for Il-actin and for avian leukosis virus (ALV) proteins. Proviral ALV DNA was integrated into host cell DNA by prior infection with ALV. Within 1 h after influenza virus infection, the rate of transcription of I-actin and ALV sequences decreased 40 to 60%, as determined by labeling the cells for 5 min with [3H]uridine and by in vitro, runoff assays with isolated nuclei. The transcripts that continued to be synthesized did not appear in the cytoplasm as mature mRNAs, and the kinetics of labeling of these transcripts strongly suggest that they were degraded in the nucleus. By Sl endonuclease assay, it was confirmed that nuclear ALV transcripts disappeared very early after infection, already decreasing ca. 80% by 1 h postinfection. A plausible explanation for this nuclear degradation is that the viral cap-dependent endonuclease in the nucleus cleaves the 5' ends of new polymerase II transcripts, rendering the resulting decapped RNAs susceptible to hydrolysis by cellular nucleases. In contrast to the nuclear transcripts, cytoplasmic ,I-actin and ALV mRNAs, which are synthesized before infection, were more stable and did not decrease in amount until after 3 h postinfection. Similar stability of cytoplasmic host cell mRNAs was observed in infected HeLa cells, in which the levels of actin mRNA and two HeLa cell mRNAs (pHe 7 and pHe 28) remained at undiminished levels for 3 h of infection and decreased only slightly by 4.5 h postinfection. The cytoplasmic actin and pHe 7 mRNAs isolated from infected HeLa cells were shown to be translated in reticulocyte extracts in vitro, indicating that host mRNAs were not inactivated by a virus-induced modification. Despite the continued presence of high levels of functional host cell mRNAs, host cell protein synthesis was effectively shut off by about 3 h postinfection in both chicken embryo fibroblasts and HeLa cells. These results are consistent with the establishment of an influenza virus-specific translational system that selectively translates viral and not host mRNAs.Various DNA and RNA viruses have distinct effects on the expression of host cell mRNAs. Some of these effects are on nuclear events, e.g., an inhibition of RNA polymerase II transcription (6, 21, 22, 32) or a selective inhibition of the transport of host cell mRNAs to the cytoplasm (1, 11). Even so-called cytoplasmic RNA viruses such as poliovirus and vesicular stomatitis virus cause an inhibition of nuclear polymerase II transcription (6,21,22). Other viral effects occur in the cytoplasm, e.g., the establishment of translational machinery that selectively translates viral and not host mRNAs (9, 35) and the selective degradation of cytoplasmic host cell mRNAs (16,23,26).We undertook the present study to examine the effects of influenza virus infection on the expression of host cell mRNAs. Effects may be expected in both the nucleus and the cytoplasm. Influe...

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“…In general, there is good agreement that an intact 5' cap is essential for mRNA stability, although the extent of destabilization attributable to decapping varies significantly for different mRNAs (17,19,23,36,40,48). The hypothesis that mRNA stability is a function of target size was initially supported by studies of mRNA populations (52,58,78,81).…”

Section: Discussionmentioning

confidence: 99%

Determinants of mRNA stability in Dictyostelium discoideum amoebae: differences in poly(A) tail length, ribosome loading, and mRNA size cannot account for the heterogeneity of mRNA decay rates.

Shapiro¹,

Herrick²,

Manrow³

et al. 1988

Mol. Cell. Biol.

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As an approach to understanding the structures and mechanisms which determine mRNA decay rates, we have cloned and begun to characterize cDNAs which encode mRNAs representative of the stability extremes in the poly(A)+ RNA population of Dictyostelium discoideum amoebae. The cDNA clones were identified in a screening procedure which was based on the occurrence of poly(A) shortening during mRNA aging. mRNA half-lives were determined by hybridization of poly(A)+ RNA, isolated from cells labeled in a 32P04 pulse-chase, to dots of excess cloned DNA. Individual mRNAs decayed with unique first-order decay rates ranging from 0.9 to 9.6 h, indicating that the complex decay kinetics of total poly(A)+ RNA in D. discoideum amoebae reflect the sum of the decay rates of individual mRNAs. Using specific probes derived from these cDNA clones, we have compared the sizes, extents of ribosome loading, and poly(A) tail lengths of stable, moderately stable, and unstable mRNAs. We found (i) no correlation between mRNA size and decay rate; (ii) no significant difference in the number of ribosomes per unit length of stable versus unstable mRNAs, and (iii) a general inverse relationship between mRNA decay rates and poly(A) tail lengths. Collectively, these observations indicate that mRNA decay in D. discoideum amoebae cannot be explained in terms of random nucleolytic events. The possibility that specific 3'-structural determinants can confer mRNA instability is suggested by a comparison of the labeling and turnover kinetics of different actin mRNAs. A correlation was observed between the steady-state percentage of a given mRNA found in polysomes and its degree of instability; i.e., unstable mRNAs were more efficiently recruited into polysomes than stable mRNAs. Since stable mRNAs are, on average, "older" than unstable mRNAs, this correlation may reflect a translational role for mRNA modifications that change in a time-dependent manner. Our previous studies have demonstrated both a time-dependent shortening and a possible translational role for the 3' poly(A) tracts of mRNA. We suggest, therefore, that the observed differences in the translational efficiency of stable and unstable mRNAs may, in part, be attributable to differences in steady-state poly(A) tail lengths.We have previously demonstrated that the mRNA population in vegetatively growing amoebae of the cellular slime mold Dictyostelium discoideum decays with complex kinetics, consisting of at least two major components: a rapidly decaying component with a half-life of approximately 50 min, and a long-lived component with a half-life of approximately 10 h (14, 58). Similar complex kinetics have been observed for the decay of poly(A)+ RNA in a variety of other eucaryotic cells (5,25,39,57,77,78,81). It is likely that these complex decay kinetics reflect the sum of the decay rates of individual mRNAs (e.g., in D. discoideum, the most stable mRNAs have half-lives of approximately 10 h and the least stable mRNAs have half-lives which are approximately 10-fold shorter). It has been s...

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Requirement for 7-methylguanosine in translation of globin mRNA in vivo

Cited by 60 publications

References 35 publications

Expression of mRNA electroporated into plant and animal cells

Expression of mRNA electroporated into plant and animal cells

Metabolism and expression of RNA polymerase II transcripts in influenza virus-infected cells.

Determinants of mRNA stability in Dictyostelium discoideum amoebae: differences in poly(A) tail length, ribosome loading, and mRNA size cannot account for the heterogeneity of mRNA decay rates.

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