Mechanism of ϵ15 conversion studied with a bacterial mutant

Losick, Richard; Robbins, P. W.

doi:10.1016/0022-2836(67)90361-0

Cited by 63 publications

(26 citation statements)

References 11 publications

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“…The fact that curing TUSoD11 rendered it capable of adsorbing wEf11 supports the notion that lysogeny either altered or eliminated the phage receptor on the cell surface. Prophage-mediated modification of phage receptors has been long known and well documented for several other phage/host systems (Uetake et al, 1958;Holloway & Cooper, 1962;Losick & Robbins, 1967;Castillo & Bartell, 1974;Gemski et al, 1975;Kuzio & Kropinski, 1983;Tomás & Kay, 1984). Enzymes specified by these phages catalyse modifications of phage receptor sites (e.g.…”

Section: Discussionmentioning

confidence: 99%

Genetic modifications to temperate Enterococcus faecalis phage ϕEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection

et al. 2013

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Section: Discussionmentioning

confidence: 99%

Genetic modifications to temperate Enterococcus faecalis phage ϕEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection

et al. 2013

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“…Simultaneously, the cells become both immune and resistant to superinfection by D3. Extrapolating from the work with Salmonella phage ε15 (6,45,46), I hypothesized that three phage gene products might be involved in the conversion: an inhibitor of the ␣-polymerase, a new ␤-polymerase, and a fucosamine O-acetylase. Extensive early attempts to clone the conversion genes failed.…”

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confidence: 99%

Sequence of the Genome of the Temperate, Serotype-Converting, Pseudomonas aeruginosa Bacteriophage D3

Kropinski

2000

J Bacteriol

104

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Temperate bacteriophage D3, a member of the virus family Siphoviridae, is responsible for serotype conversion in its host, Pseudomonas aeruginosa. The complete sequence of the double-stranded DNA genome has been determined. The 56,426 bp contains 90 putative open reading frames (ORFs) and four genes specifying tRNAs. The latter are specific for methionine (AUG), glycine (GGA), asparagine (AAC), and threonine (ACA). The tRNAs may function in the translation of certain highly expressed proteins from this relatively AT-rich genome. D3 proteins which exhibited a high degree of sequence similarity to previously characterized phage proteins included the portal, major head, tail, and tail tape measure proteins, endolysin, integrase, helicase, and NinG. The layout of genes was reminiscent of lambdoid phages, with the exception of the placement of the endolysin gene, which parenthetically also lacked a cognate holin. The greatest sequence similarity was found in the morphogenesis genes to coliphages HK022 and HK97. Among the ORFs was discovered the gene encoding the fucosamine O-acetylase, which is in part responsible for the serotype conversion events.Upon infection of sensitive cells, the genomes of temperate bacteriophages have two pathways open to them: development associated with cell lysis and the release of progeny (lytic response), or repression of lytic development usually associated with integration into the host chromosome and maintenance in a quiescent state (lysogenic response). The best studied of the temperate phages is bacteriophage lambda, which infects Escherichia coli strains. This phage is the archetype of a group of phylogenetically related viruses called the lambdoid phages. In many cases temperate phages also alter the phenotype of the lysogenized cells, resulting in the production of toxins or expression of surface components resulting in alterations to the cells' antigenicity. This phenomenon is called lysogenic conversion.Bacteriophage D3 was obtained from a clinical isolate of Pseudomonas aeruginosa by Holloway et al. (35), who noted subsequently that lysogenization of host cells by phage D3 resulted in a change in the cells' serological properties (34). Kuzio and Kropinski showed that the lipopolysaccharide isolated from the lysogens [PAO(D3)] lacked receptor activity for this phage and that the O-antigenic polysaccharide side chains were chemically altered (41). Specifically, the hydroxyl group at position 4 of the D-fucosamine residues became acetylated, and the bonding between the trisaccharide repeats changed from ␣134 to ␤134. This results in the change of serotype from International Antigenic Typing Scheme O5 to O16/20 (42, 43). Simultaneously, the cells become both immune and resistant to superinfection by D3. Extrapolating from the work with Salmonella phage ε15 (6, 45, 46), I hypothesized that three phage gene products might be involved in the conversion: an inhibitor of the ␣-polymerase, a new ␤-polymerase, and a fucosamine O-acetylase. Extensive early attempts to clone the conversi...

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“…Mutants of the SR LPS phenotype have been identified in Salmonella groups B and E (22,30). In S. typhimurium (group B), the rfc locus has been located between gal and trp (30,44), corresponding to a map position between 18 and 34 min.…”

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confidence: 99%

Molecular cloning, characterization, and nucleotide sequence of the rfc gene, which encodes an O-antigen polymerase of Salmonella typhimurium

Collins

Hackett

1991

J Bacteriol

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The rfc gene of Salmonella typhimurium was located in a 1.75-kb HindIII fragment and restored wild-type lipopolysaccharide synthesis ability to both an older rfc point mutant and new rfc::IS10 mutants. DNA sequencing of the HindIll fragment revealed an open reading frame which could encode a protein of 407 amino acids with an Mr of 47,472 and also revealed potential translation signals. Modulator codons accounted for 12.5% of the total codon content, providing a possible explanation for the nondetectability of the protein in subcellular systems. Secondary structure analysis suggested the presence of transmembrane ,(-sheet structures, implying a possible role for the protein in translocation of hydrophilic 0-antigen-containing materials.Salmonella strains of groups A, B, and Dl contained rfc-homologous DNA, but strains of groups Cl, C2, C3, D2, and E2 did not.Three major genetic regions have been implicated as dedicated to the biosynthesis of the polysaccharide component of the lipopolysaccharide (LPS) of Salmonella typhimurium. The rfa cluster of genes is involved in core synthesis, and the rfb region is involved in the synthesis of the 0-antigenic tetrasaccharide units (26). In addition, it is thought that genes of both the rfa and rfb clusters are involved in the transport and ligation of core-0-antigen complexes (26). The rfc region is thought to encode a polymerase responsible for the linking of the 0-antigen tetrasaccharide units into long chains, giving rise to typical smooth LPS (26). Mutants of S. typhimurium which are defective in the 0-antigen polymerase because of a mutation at the rfc locus produce LPS structures termed semirough (SR), which have at most one 0-antigenic tetrasaccharide unit attached to any given core unit (30,56). A bacteriophage sensitivity pattern characteristic of SR mutants has been described previously; such strains of S. typhimurium were resistant to the smooth LPS-specific phages 9NA and P22, sensitive to phage FO, and resistant to all phages specific for rough LPS (LPS without attached 0 antigen) except P22I (55).Mutants of the SR LPS phenotype have been identified in Salmonella groups B and E (22, 30). In S. typhimurium (group B), the rfc locus has been located between gal and trp (30, 44), corresponding to a map position between 18 and 34 min. An analogous locus in some Salmonella strains of group D has been postulated on the basis of the observation that in hybrids between Salmonella groups B (0-4, 5, 12) and D (0-9, 12), involving transfer of rib genes, the polymerase of one group could polymerize the 0 units of the other (24,31,51 This paper describes the cloning of the rfc gene of S. typhimurium by complementation of rfc defects in spontaneous and ISl0-derived SR mutants. A physical map of the DNA region encoding the rfc gene is presented, and attempts to visualize the gene product(s) are described. The distribution of rfc-homologous DNA in other Salmonella strains is also determined. The DNA fragment containing the gene is sequenced, and a putative rfc gene is ident...

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Mechanism of ϵ15 conversion studied with a bacterial mutant

Cited by 63 publications

References 11 publications

Genetic modifications to temperate Enterococcus faecalis phage ϕEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection

Genetic modifications to temperate Enterococcus faecalis phage ϕEf11 that abolish the establishment of lysogeny and sensitivity to repressor, and increase host range and productivity of lytic infection

Sequence of the Genome of the Temperate, Serotype-Converting, Pseudomonas aeruginosa Bacteriophage D3

Molecular cloning, characterization, and nucleotide sequence of the rfc gene, which encodes an O-antigen polymerase of Salmonella typhimurium

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