Selection of mRNA by Ribosomes During Prokaryotic Translational Initiation

Gualerzi, Claudio O.; Calogero, Raffaele Adolfo; Canonaco, Maria A.; Brombach, Martin; Pon, Cynthia L.

doi:10.1007/978-3-642-73139-6_25

Cited by 13 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Investigations of the E. coli atp operon provided insight into the mechanism by which this local control can be achieved (313). Small in vitro-synthesized fragments of the atp operon containing the TIRs of individual genes were allowed to interact with purified 30S subunits and fMet-tRNA fMet , and the resulting complexes were analyzed by toeprinting (203), sucrose gradients (189), and runoff polypeptide incorporation assays. The results revealed that structure in the atpG TIR fragment, which supported very poor initiation, interfered with 30S binding whereas the efficient atpE TIR supported both efficient initiation and strong 30S binding.…”

Section: -End-dependent Initiationmentioning

confidence: 99%

Posttranscriptional Control of Gene Expression in Yeast

McCarthy

1998

Microbiol Mol Biol Rev

212

133

View full text Add to dashboard Cite

SUMMARY Studies of the budding yeast Saccharomyces cerevisiae have greatly advanced our understanding of the posttranscriptional steps of eukaryotic gene expression. Given the wide range of experimental tools applicable to S. cerevisiae and the recent determination of its complete genomic sequence, many of the key challenges of the posttranscriptional control field can be tackled particularly effectively by using this organism. This article reviews the current knowledge of the cellular components and mechanisms related to translation and mRNA decay, with the emphasis on the molecular basis for rate control and gene regulation. Recent progress in characterizing translation factors and their protein-protein and RNA-protein interactions has been rapid. Against the background of a growing body of structural information, the review discusses the thermodynamic and kinetic principles that govern the translation process. As in prokaryotic systems, translational initiation is a key point of control. Modulation of the activities of translational initiation factors imposes global regulation in the cell, while structural features of particular 5′ untranslated regions, such as upstream open reading frames and effector binding sites, allow for gene-specific regulation. Recent data have revealed many new details of the molecular mechanisms involved while providing insight into the functional overlaps and molecular networking that are apparently a key feature of evolving cellular systems. An overall picture of the mechanisms governing mRNA decay has only very recently begun to develop. The latest work has revealed new information about the mRNA decay pathways, the components of the mRNA degradation machinery, and the way in which these might relate to the translation apparatus. Overall, major challenges still to be addressed include the task of relating principles of posttranscriptional control to cellular compartmentalization and polysome structure and the role of molecular channelling in these highly complex expression systems.

show abstract

Section: -End-dependent Initiationmentioning

confidence: 99%

Posttranscriptional Control of Gene Expression in Yeast

McCarthy

1998

Microbiol Mol Biol Rev

212

133

View full text Add to dashboard Cite

show abstract

“…Sci. USA 85 (1988) 6431 (5), and it further emphasizes that it is the kinetics of formation and not the equilibrium levels of the 30S and 70S initiation complexes that determine the final level of protein synthesis (5,19). From Avogadro's number it can be estimated that within the hemisphere described by the free rotation of an AUG triplet separated by a 7-nucleotide spacer from an SD sequence base-paired to the 30S subunits, the concentration of the initiation triplet is .20 mM.…”

Section: Designmentioning

confidence: 99%

Selection of the mRNA translation initiation region by Escherichia coli ribosomes.

Calogero

Pon

Canonaco

et al. 1988

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

153

133

View full text Add to dashboard Cite

Two genes specifying model mRNAs of minimal size and coding capacity, with or without the ShineDalgarno (SD) sequence, were assembled, cloned, and transcribed in high yields. These mRNAs, as well as synthetic polynucleotides, phage MS2 RNA, and a deoxyoctanucleotide complementary to the 3' end of 16S rRNA were used to study the mechanism of translation initiation in vitro. Escherichia coli 30S ribosomal subunits interact with all these nucleic acids, albeit with different affinities; the affinity for the mRNA with the SD sequence (Ka ==2 x 10 M-1) is more than an order of magnitude higher than that for the mRNA lacking this sequence. The initiation factors are equally required, regardless of the presence of the SD sequence, for 30S and 70S initiation complex formation and for mRNA translation, but the initiation factors do not affect the SD interaction or the binding of the mRNAs to the ribosomes. The SD interaction is also mechanistically irrelevant for 30S initiation complex formation and is not essential for translation in vitro or for the selection of the mRNA reading frame. It is suggested that the function of the SD interaction is to ensure a high concentration of the initiation triplet near the ribosomal peptidyl-tRNA binding site, whereas the selection of the translational start is achieved kinetically, under the influence of the initiation factors, during decoding of the iinitiator tRNA.Gene expression ultimately depends on how efficiently and accurately each mRNA translation initiation region is selected by the ribosomes, but we are often unable to rationalize why some genes are either poorly or highly expressed at the translational level (for reviews, see refs. 1-6).Comparison of several hundred translation initiation regions allowed the identification of a rather loose consensus sequence (1-3) and the conclusion that this region preferentially contains bases (i.e., adenine and uracil) that minimize secondary structure formation and includes an initiation triplet (AUG in >90% of the cases) (3). The initiation triplet is often preceded by a purine-rich Shine-Dalgarno (SD) sequence of variable length and potential complementarity to the 3' end of 16S rRNA (the anti-SD sequence). The SD sequence is separated from the initiation triplet by a spacer, most frequently 7-9 bases long (7,8). Convincing evidence for the participation of the SD sequence in initiation has been obtained (9, 10), but its precise function is unknown.To further the studies on the mechanism of translation and, more specifically, on mRNA-ribosome interaction at initiation, we designed, assembled, and expressed in vitro, a gene specifying a model mRNA (designated 002 mRNA) of minimal size and coding capacity containing the canonical translation initiation region of natural mRNAs. Deletion of a restriction fragment from this gene allowed us to compare the activity of two mRNAs identical to each other except for the presence of the SD sequence and to ask if the ribosomal binding of mRNA is different with natural and synthetic mRNA...

show abstract

“…In addition, they always involve the interaction of the start codon with the anti-eodon of fMet-tRNA ~t associated with the 30S ribosomal subunit. It has been proposed that the SD interaction is mechanistically irrelevant " [2,3], but rather serves to ensure a high concentration of a start codon close to the ribosomal P site [3]. Since the kinetics of ternary complex formation appears to be primarily depen-dent on decoding of the fMet-tRNA fMet, a "good' SD domain could aid in mRNA selection [3], and thus provide competitiveness for a particular mRNA in vivo.…”

Section: Introductionmentioning

confidence: 99%

Ternary complex formation on leaderless phage mRNA

Resch¹

1995

FEMS Microbiology Reviews

View full text Add to dashboard Cite

The phage Lambda PRM promoter-derived cl mRNA and phage P2 gene V mRNA are transcribed beginning with the A residue of the AUG start codon. Using lacZ fusion analysis we have assessed the effects of alterations in the immediate downstream coding region on the translational efficiency of these rnRNAs. Mutations, including deletions of the putative downstream box of either cl or gene V mRNAs, showed no significant reduction in expression of the different lacZ fusions. Primer extension inhibition analysis suggests a role of ribosomal protein S1 in cl mRNA recognition.

show abstract

Selection of mRNA by Ribosomes During Prokaryotic Translational Initiation

Cited by 13 publications

References 29 publications

Posttranscriptional Control of Gene Expression in Yeast

Posttranscriptional Control of Gene Expression in Yeast

Selection of the mRNA translation initiation region by Escherichia coli ribosomes.

Ternary complex formation on leaderless phage mRNA

Contact Info

Product

Resources

About