Dual translational initiation sites control function of the lambda S gene.

Bläsi, Udo; Nam, Kiebang; Hartz, Dieter; Gold, Larry; Young, Ryland

doi:10.1002/j.1460-2075.1989.tb08515.x

Cited by 83 publications

(125 citation statements)

References 36 publications

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“…In (e), the lethal form of S 21 is shown with its TMD1 in the periplasm. (C) Translational control region of the and 21 holin genes (11,15,16). Filled and empty stars show starts of the long (antiholin) and short (holin) gene products.…”

Section: Resultsmentioning

confidence: 99%

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Topological dynamics of holins in programmed bacterial lysis

Park

Struck

Deaton

et al. 2006

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

102

162

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The fate of phage-infected bacteria is determined by the holin, a small membrane protein that triggers to disrupt the membrane at a programmed time, allowing a lysozyme to attack the cell wall. S 21 68, the holin of phage 21, has two transmembrane domains (TMDs) with a predicted N-in, C-in topology. Surprisingly, TMD1 of S 21 68 was found to be dispensable for function, to behave as a SAR (''signal-anchor-release'') domain in exiting the membrane to the periplasm, and to engage in homotypic interactions in the soluble phase. The departure of TMD1 from the bilayer coincides with the lethal triggering of the holin and is accelerated by membrane depolarization. Basic residues added at the N terminus of S 21 68 prevent the escape of TMD1 to the periplasm and block hole formation by TMD2. Lysis thus depends on dynamic topology, in that removal of the inhibitory TMD1 from the bilayer frees TMD2 for programmed formation of lethal membrane lesions.bacteriophage ͉ GxxxG motif ͉ SAR domain ͉ transmembrane domain

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Section: Resultsmentioning

confidence: 99%

“…1C). Both Met codons are used for translational initiation, giving rise to two proteins, S107 and S105, named for their length in amino acid residues (6,(10)(11)(12). These two proteins differ only at their N termini, where S107 has a Met-Lys extension with respect to S105.…”

mentioning

confidence: 99%

Topological dynamics of holins in programmed bacterial lysis

Park

Struck

Deaton

et al. 2006

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

102

162

View full text Add to dashboard Cite

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“…In these reports, the efficiency of the upstream site seems to be limited by mRNA secondary structures which overlap translational initiation sites. The stability of such regulatory structures, which can be as little as -6.3 kcal/mol in the case of the X S gene product (Biiasi et al, 1989), are related to their inhibitory effect on translational initiation (Blasi et al, 1989;Hall et al, 1982). Inefficient loading of ribosomes at the upstream sequence allows more efficient initiation at the downstream site (Blasi et al, 1989;Kofoid and Parkinson, 1991).…”

Section: Resultsmentioning

confidence: 99%

Autogenous transcriptional activation of a thiostrepton-induced gene in Streptomyces lividans.

1993

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Although the antibiotic thiostrepton is best known as an inhibitor of protein synthesis, it also, at extremely low concentrations (< 10-9 M), induces the expression of a regulon of unknown function in certain Streptomyces species. Here, we report the purification of a Streptomyces lividans thiostrepton-induced transcriptional activator protein, TipAL, whose N-terminus is similar to a family of eubacterial regulatory proteins represented by MerR.TipAL was first purified from induced cultures of S.lividans as a factor which bound to and activated transcription from its own promoter. The tipAL gene was overexpressed in Escherichia coli and TipAL protein purifi'ed in a single step using a thiostrepton affinity column. Thiostrepton enhanced binding of TipAL to the promoter and catalysed specific transcription in vitro.TipAs, a second gene product of the same open reading frame consisting of the C-terminal domain of TipAL, is apparently translated using its own in-frame initiation site. Since it is produced in large molar excess relative to TipAL after induction and also binds thiostrepton, it may competitively modulate transcriptional activation.

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“…Using toeprinting (Winter et al 1987;Hartz et al 1988Hartz et al , 1989McPheeters et al 1988;Blasi et al 1989;Schaefer et al 1989) as the assay for tRNA binding in 30S initiation complexes, we tested initiator tRNA fragments and several mutant fragments for their ability to be selected by IF3 on various initiation codons. …”

mentioning

confidence: 99%

Domains of initiator tRNA and initiation codon crucial for initiator tRNA selection by Escherichia coli IF3.

Hartz¹,

Binkley²,

et al. 1990

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Initiation factors are used by Escherichia cob to select the initiator tRNA over elongator tRNAs during translation initiation. IF3 appears to "inspect" the anticodon end of the tRNA, probably along with the initiation codon. The anticodon stem and loop of the initiator tRNA, together with part of the initiation codon of the mRNA, can be thought of as a unit. Changes made in the anticodon stem, the anticodon loop, or the anticodon of an initiator tRNA fragment result in a loss of selection by IF3 in an in vitro assay for translation initiation. IF3 allows the selection of an initiator tRNA anticodon stem and loop fragment on GUG and UUG codons but does not select that tRNA fragment in response to AUU. Escherichia coli initiation factor IF3 is involved in several aspects of translation initiation; IF3 (together with IF1) helps in the dissociation of 70S ribosomes into 30S and 50S subunits (Kaempfer 1972;Godefroy-Colburn et al. 1975), catalyzes the formation of 30S initiation complexes (Wintermeyer and Gualerzi 1983), and selects the initiator tRNA against elongator tRNAs in those complexes . The selection of the initiator tRNA by IF3 is based on the unique RNA part of the initiator tRNA (Risuleo et al. 1976), and, most likely, sequences located in the anticodon stem and loop . The three GC base pairs of the anticodon stem adjacent to the loop of the initiator tRNA are important for initiation complex formation and in vitro translation (Seong and RajBhandary 1987), suggesting that this part of the anticodon stem might be important for recognition by IF3. Berkhout et al. (1986) showed that IF3 excludes initiator tRNA on a UUU codon, as though the initiation codon, itself, might be part of the recognition motif explored by IF3 during selection of the initiator tRNA.We have examined those features of the initiator tRNA that are required for selection by IF3. Using toeprinting (Winter et al. 1987;Hartz et al. 1988Hartz et al. , 1989McPheeters et al. 1988;Blasi et al. 1989;Schaefer et al. 1989) as the assay for tRNA binding in 30S initiation complexes, we tested initiator tRNA fragments and several mutant fragments for their ability to be selected by IF3 on various initiation codons. ResultsTo analyze 30S complex formation on various translation initiation sites, we used the extension inhibition technique, also called toeprinting, cDNA synthesis on a template mRNA is terminated when the reverse transcriptase encounters a 30S ribosomal subunit plus tRNA bound on the mRNA. The short cDNA is visualized as a toeprint band on a sequencing gel. The toeprint usually appears 15 bases downstream of the A of the initiation codon if initiator tRNA is bound in the complex or at + 15 from the first base of the cognate codon if elongator tRNA is bound. When compared to the band of the fulllength cDNA, the toeprint band is a quantitative measure of ternary complex formation . Variations of A22~ etUsing the toeprinting assay, we have shown previously that the synthetic initiator tRNA fragment A22~ et (Fig. 1) behaves very similarly ...

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Dual translational initiation sites control function of the lambda S gene.

Cited by 83 publications

References 36 publications

Topological dynamics of holins in programmed bacterial lysis

Topological dynamics of holins in programmed bacterial lysis

Autogenous transcriptional activation of a thiostrepton-induced gene in Streptomyces lividans.

Domains of initiator tRNA and initiation codon crucial for initiator tRNA selection by Escherichia coli IF3.

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