Translation efficiency of zein mRNA is reduced by hybrid formation between the 5′- and 3′-untranslated region

Spena, Angelo; Krause, E.; Dobberstein, Bernhard

doi:10.1002/j.1460-2075.1985.tb03909.x

Cited by 60 publications

(33 citation statements)

References 40 publications

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“…This may suggest a direct involvement of O2 in the transcription of some members of the other subsets (presently under investigation) or an indirect effect of the lowered zH polypeptide accumulation on the intracellular stability of macromolecules and of other storage proteins because of improper filling in of the protein bodies. In this respect translatability and stability of zein mRNA could impact zein polypeptides accumulation (Spena et al, 1985;Plotnikov and Bakaldina, 1996) and partly explain zein pattern variations among GBs. The studies on light-and heavy-zein transcript stabilities in the W64A GB carrying the O2w1 allele or the o2T allele indicated that the half-life of the two transcript populations is different with, however, an higher stability for the light transcripts in the mutant genotype.…”

Section: Discussionmentioning

confidence: 99%

“…It should be noted, however, that the amount of heavy chain polypeptides determined at a given stage of development or at maturity represents an accumulation. On the contrary the transcript datum represents a steady-state level, which should not necessarily reflect the final abundance of H polypeptides, as cytoplasmic control mechanisms for the translational efficiency of zH mRNA have been put forward (Spena et al, 1985;Kodrzycki et al, 1989). Table I).…”

Section: Heavy Chain Zein Transcripts Occur In O2 Linesmentioning

confidence: 99%

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Specific Combinations of Zein Genes and Genetic Backgrounds Influence the Transcription of the Heavy-Chain Zein Genes in Maizeopaque-2 Endosperms

et al. 2000

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The transcript levels of heavy-chain zein genes (zH1 and zH2) and the occurrence of the zH polypeptides in different opaque-2 (o2) lines were investigated by RNA-blot analyses and by sodium dodecylsulfate-polyacrylamide gel electrophoresis or two-dimensional gel electrophoresis protein fractionations. Four mutant alleles o2R, o2T, o2It, and o2-676 introgressed into different genetic backgrounds (GBs) were considered. The mono-dimensional gel electrophoresis zein pattern can be either conserved or different among the various GBs carrying the same o2 allele. Likewise, in the identical GB carrying different o2 alleles, the zein pattern can be either conserved or differentially affected by the different mutant allele. Zein protein analysis of reciprocal crosses between lines with different o2 alleles or the same o2 showed in some case a more than additive zH pattern in respect to the o2 parent lines. Electrophoretic mobility shift assay approaches, with O2-binding oligonucleotide and endosperm extracts from the above o2 lines, failed to reveal o2-specific retarded band in any of the o2 extracts. The results suggest that the promoter of some zH1 and zH2 contains motif(s) that can respond to factors other than O2.

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Section: Discussionmentioning

confidence: 99%

Section: Heavy Chain Zein Transcripts Occur In O2 Linesmentioning

confidence: 99%

Specific Combinations of Zein Genes and Genetic Backgrounds Influence the Transcription of the Heavy-Chain Zein Genes in Maizeopaque-2 Endosperms

et al. 2000

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“…Long-range base pairings are known to form in some bacterial transcripts (2,3,25), and there is one published report of repression of eucaryotic translation in vitro by pairing between 5' and 3' noncoding sequences (33). Here I show that inhibition of translation by long-range interactions can also be demonstrated in the cytoplasm of transfected cells, where the inhibition depends on the composition of the culture medium and, in an interesting way, on the precise location of the complementary sequences within the mRNA.…”

Section: Discussionmentioning

confidence: 99%

Circumstances and mechanisms of inhibition of translation by secondary structure in eucaryotic mRNAs.

Kozak¹

1989

Mol. Cell. Biol.

595

467

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This paper describes in vitro experiments with two types of intramolecular duplex structures that inhibit translation in cis by preventing the formation of an initiation complex or by causing the complex to be abortive. One stem-loop structure (AG = -30 kcal/mol) prevented mRNA from engaging 40S subunits when the hairpin occurred 12 nucleotides (nt) from the cap but had no deleterious effect when it was repositioned 52 nt from the cap. This result confirms prior in vivo evidence that the 40S subunit-factor complex, once bound to mRNA, has considerable ability to penetrate secondary structure. Consequently, translation is most sensitive to secondary structure at the entry site for ribosomes, i.e., the 5' end of the mRNA. The second stem-loop structure (hp7; AG = -61 kcal/mol, located 72 nt from the cap) was too stable to be unwound by 40S ribosomes. hp7 did not prevent a 40S ribosomal subunit from binding but caused the 40S subunit to stall on the 5' side of the hairpin, exactly as the scanning model predicts. Control experiments revealed that 80S elongating ribosomes could disrupt duplex structures, such as hp7, that were too stable to be penetrated by the scanning 40S ribosome-factor complex. A third type of base-paired structure shown to inhibit translation in vivo involves a long-range interaction between the 5' and 3' noncoding sequences.The scanning model for initiation in eucaryotes postulates three steps in the association of mRNA with 40S ribosomal subunits: binding of a 40S ribosomal subunit-factor complex to the capped 5' end of the mRNA (step 1), followed by linear migration (step 2) which ends when the 40S subunit reaches (usually) the first AUG codon (step 3).Step 1 is facilitated by the m7G cap (29) and a well-characterized cap-binding protein (30).Step 3, recognition of the AUG codon, is mediated by eIF2-modulated base pairing with the anticodon in Met-tRNAMet (5,6) and, at least in higher eucaryotes, by a consensus sequence that flanks the AUG codon (12,14,15). Step 2 is supported by evidence that is provocative but indirect, namely, the effects of the antibiotic edeine on formation of initiation complexes (22) The aforementioned finding emerged in the course of a broader study of the circumstances and cis-limited mechanisms of inhibition of translation by mRNA secondary structure. There have been numerous reports concerning the ability of secondary structure to inhibit translation of eucaryotic mRNAs in vivo (reviewed in reference 17; see also Discussion). Here I have resorted to cell-free translation systems to study the level at which translation is blocked by two specific structures: (i) a moderately stable hairpin (AG = -30 kcal/mol) which does not inhibit translation when it occurs around the AUG initiator codon (i.e., some distance downstream from the cap) but does inhibit when it is moved close to the 5' end of the transcript and (ii) a very stable hairpin (AG = -61 kcallmol) which inhibits, no matter where it occurs within the 5' noncoding region, by halting the migration of 40S ribosom...

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“…In higher eucaryotes, translational efficiency has been correlated with the accessibility of the 5' cap (9,10). In addition, translational efficiency of zein mRNA is reduced by duplex formation between the 5'-and 3'-untranslated regions (51). Duplex formation between 5'-and 3'-untranslated regions could explain the diminished translation of mRNA from certain cycl-512 revertants (64).…”

Section: Discussionmentioning

confidence: 99%

mRNA structures influencing translation in the yeast Saccharomyces cerevisiae.

Baim¹,

Sherman²

1988

Mol. Cell. Biol.

160

114

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The mRNA sequence and structures that modify and are required for translation of iso-1-cytochrome c in the yeast Saccharomyces cerevisiae were investigated with sets of CYCI alleles having alterations in the 5' leader region. Measurements of levels of CYCI mRNA and iso-1-cytochrome c in strains having single copies of altered alleles with nested deletions led to the conclusion that there is no specific sequence adjacent to the AUG initiator codon required for efficient translation. However, the nucleotides preceding the AUG initiator codon at positions -1 and -3 slightly modified the efficiency of translation to an order of preference similar to that found in higher cells. In contrast to large effects observed in higher eucaryotes, the magnitude of this AUG context effect in S. cerevisiae was only two-to threefold. Furthermore, introduction of hairpin structures in the vicinity of the AUG initiator codon inhibited translation, with the degree of inhibition related to the stability and proximity of the hairpin. These results with S. cerevisiae and published findings on other organisms suggest that translation in S. cerevisiae is more sensitive to secondary structures than is translation in higher eucaryotes.Mutational alterations at the end of the CYCI gene in Saccharomyces cerevisiae previously have been used to investigate the nucleotide sequences in mRNA that are required for translation of its gene product, iso-1-cytochrome c. Protein analysis of iso-1-cytochrome c from certain cycl revertants and the corresponding deduced DNA sequences of the cycl mutations led Stewart et al. (54) and Sherman and Stewart (45) to conclude that AUG was the only codon capable of initiating translation at appreciable levels. Of the remaining 63 codons, only the UGG codon was not excluded as being a potential initiator codon (41). Early work also indicated that translation of CYC1 mRNA initiated at the most 5'-proximal AUG (43-45). Furthermore, translation could initiate with equal or nearly equal efficiency at a relocated AUG initiator codon within a 37-nucleotide region around the normal initiation site (43)(44)(45)54), suggesting a lack of any additional sequence requirements for initiation in S. cerevisiae analogous to the essential ribosome-binding site present in bacterial mRNA (53). However, the nucleotides immediately 5' to the AUG initiator codon in CYCI mRNA were observed to influence the efficiency of translation slightly, although precise rules were not established (45).In the present study, we analyzed the structural elements that influence the translational efficiency of CYCI mRNA. Earlier studies relied on mutation and recombination produced in vivo, whereas here specific alterations within the 5'-noncoding region of CYCI were produced primarily in vitro. The levels of CYCI mRNA and iso-1-cytochrome c were determined in isogenic strains, each carrying a single copy of an altered CYCI gene at the normal chromosomal position. Our results demonstrated a lack of any specific sequence requirement in the 5'-untranslated ...

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Translation efficiency of zein mRNA is reduced by hybrid formation between the 5′- and 3′-untranslated region

Cited by 60 publications

References 40 publications

Specific Combinations of Zein Genes and Genetic Backgrounds Influence the Transcription of the Heavy-Chain Zein Genes in Maizeopaque-2 Endosperms

Specific Combinations of Zein Genes and Genetic Backgrounds Influence the Transcription of the Heavy-Chain Zein Genes in Maizeopaque-2 Endosperms

Circumstances and mechanisms of inhibition of translation by secondary structure in eucaryotic mRNAs.

mRNA structures influencing translation in the yeast Saccharomyces cerevisiae.

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