Integration of bacteriophage lambda into the cryptic lambdoid prophages of Escherichia coli (original) (raw)
Related papers
Journal of bacteriology, 1992
Integration of bacteriophage P2 into the Escherichia coli genome involves recombination between two attachment sites, attP and attB, one on the phage and one on the host genome, respectively. At least 10 different attB sites have been identified over the years. In E. coli C, one site, called locI, is preferred, being occupied before any of the others. In E. coli K-12, no such preference is seen (reviewed in L. E. Bertani and E. W. Six, p. 73-143, in R. Calendar, ed., The Bacteriophages, vol. 2, 1988). The DNA sequence of locI has been determined, and it shows a core sequence of 27 nucleotides identical to attP (A. Yu, L. E. Bertani, and E. Haggard-Ljungquist, Gene 80:1-12, 1989). By inverse polymerase chain reactions, the prophage-hostjunctions of DNA extracted from P2 lysogenic strains have been amplified, cloned, and sequenced. By combining the attL and attR sequences, the attB sequences of locations II, III, and H have been deduced. The core sequence of location II had 20 matches to the 27-nucleotide core sequence of aftP; the sequences of locations III and H had 17 matches. Thus, the P2 integrase accepts at least up to 37% mismatches within the core sequence. The E. coli K-12 strains examined all contain a 639-nucleotide-long cryptic remnant of P2 at a site with a sequence similar to that of locI but that may have a different map position. The P2 remnant consists of the C-terminal part of gene D, all of gene ogr, and attR. Locations II, III, and H have been located on Kohara's physical map to positions 3670, 1570 to 1575, and 2085, respectively. P2 is a temperate phage that forms stable lysogens in several enterobacteria, including Escherichia coli C and K-12 (for a review, see reference 10). In the lysogenic stage, P2 has always been found as an integrated prophage. The integration occurs according to Campell's model by sitespecific recombination between a bacterial attachment site, attB, and the attachment site of P2, attP, giving rise to two phage-host junctions, attL and attR. At least 10 different attB sites have been defined (Table 1). In E. coli C, one site, locI, is preferred, being occupied before any of the others (6). However, in E. coli K-12, no such preference has been noted, and locations H and II are occupied with about equal probability (19). The DNA sequence of locI has been determined. It consists of 27 nucleotides (nt) identical to the so-called core sequence of P2 attP (40). If locI is replaced with the homologous chromosomal segment of K-12 by transduction, the resulting strain, although mostly C, becomes like K-12 in respect to site preference; i.e., the phage will attach to one of several sites with roughly equal probabilities (35). There is also evidence for genetic changes in the phage which modify the site preference (33). Such variant phages, called saf, are produced from a prophage established in location II. DNA sequence analysis has shown that one saf mutant has a base replacement within the attP core sequence (40). In order to clarify the site preference pattern and sequence requirements for the site-specific recombina-* Corresponding author. t This work is dedicated to our friend and colleague Berit Lundqvist, who recently died of cancer at the age of 45. She followed this work with great interest, and we deeply feel her loss.
New mutants of bacteriophage λ with a specific defect in excision from the host chromosome
Journal of Molecular Biology, 1970
Mutants of bacteriophage h have been isolated which are able to integrate efficiently into the host chromosome, but are unable to excise from the host chromosome when repression is released. These mutants (&a-) define a single complementation group distinct from the previously identified i& gene (which appears to play a critical role in both integration and excision). The xLsmutations therefore probably affect a previously unidentified X gene, which we designate &is. Functional complementation experiments with h deletions indicate that x& is located on the X genome between the int gene and the general recombination gene exo. The properties of z&s-mutants are most easily explained if the &is gene specifies a protein required for the recombination event which excises the prophage DNA.
A secondary attachment site for bacteriophage λ in trpC of E. coli
Cell, 1979
We have determined the nucleotide sequence of a secondary X attachment site in trpC. Direct sequence analysis of Atrp transducing phage DNA fragments carrying the two prophage attachment sites reveals a 6 nucleotide homology in the crossover region which is a subset of the 15 nucleotide core sequence in the primary X attachment site: GCTTTTTTATACTAA. This 6 nucleotide sequence is also present in the intact trpC genome at the attachment site, as shown by analysis of trpC mRNA spanning this region.
Analysis of the lambdoid prophage element e14 in the E. coli K-12 genome
BMC microbiology, 2004
Many sequenced bacterial genomes harbor phage-like elements or cryptic prophages. These elements have been implicated in pathogenesis, serotype conversion and phage immunity. The e14 element is a defective lambdoid prophage element present at 25 min in the E. coli K-12 genome. This prophage encodes important functional genes such as lit (T4 exclusion), mcrA (modified cytosine restriction activity) and pin (recombinase). Bioinformatic analysis of the e14 prophage sequence shows the modular nature of the e14 element which shares a large part of its sequence with the Shigella flexneri phage SfV. Based on this similarity, the regulatory region including the repressor and Cro proteins and their binding sites were identified. The protein product of b1149 was found to be a fusion of a replication protein and a terminase. The genes b1143, b1151 and b1152 were identified as putative pseudogenes. A number of duplications of the stfE tail fibre gene of the e14 are seen in plasmid p15B. A prote...
Mapping of restriction sites in the attachment site region of bacteriophage lambda
MGG Molecular & General Genetics, 1977
A fine structure map ,of the EcoRI fragment containing the lambda attachment-site region has been constructed. 38 different restriction endonucleases have been employed and 170 sites located in this fragment. In addition, sites in adjacent regions have been determined for several enzymes. Complete cleavage maps of the entire lambda genome have been obtained for endonucleases BglII, BluI, KpnI, SacI, SacII, SalI and XbaI. The strategy employed for mapping included comparison of deletion and substitution mutants, analysis of mixed digests, and detailed analysis of subfragments.
MGG Molecular & General Genetics, 1988
Substitution, insertion and deletion mutations have been constructed at the XmnI restriction site in cos2. The XmnI site is located between cosB, the site where terminase binds 2 DNA; and cosN, the site where terminase introduces staggered nicks to generate cohesive ends. Substitution mutations and deletion of a base pair (a -1 change) do not obviously affect 2 growth and DNA packaging. Changes of -2, + 2 and -3 render 2 unable to grow on host cells lacking integration host factor (IHF). The -3 mutant has a reduced burst size in IHF + cells, due to a defect in the initiation of packaging. A -7 deletion mutation is lethal. Models for the basis of these mutational effects are discussed.
Behavior of λ Bacteriophage in a Recombination Deficient Strain of Escherichia coli
Journal of Virology
The behavior of λ phage in the Rec − strain JC-1569 is compared with that in the Rec + strain JC-1557. No difference deemed significant was noted in the adsorption rate, latent period, burst size, frequency of lysogenization, and frequency of vegetative phage recombination. The location of the prophage and its mode of insertion in the Rec − lysogen of wild-type λ (λ + ) were inferred to be normal from the results of conjugational crosses. Spontaneous and ultraviolet (UV) irradiation induction of λ + were markedly reduced in the Rec − lysogen. On the other hand, thermal induction of a mutant lambda (λ cI857 ) lysogen of the Rec − strain was not reduced and was only slightly affected by UV irradiation. Phage subject to inhibition by λ immunity failed to multiply in UV-irradiated cells of the Rec − λ + lysogen, whereas those not inhibited by this immunity did multiply. It was concluded that the failure of UV to induce λ + in the Rec − lysogen was not due to damage to the prophage, but ...
Virology, 2014
The Escherichia coli bacteriophage P1 packages host chromosome separately from phage DNA, and transfers it to recipient cells at low frequency in a process called generalized transduction. Phage genomes are packaged from concatemers beginning at a specific site, pac. To increase transduction rate, we have inserted pac into the chromosome at up to five equally spaced positions; at least this many are fully tolerated in the absence of P1 infection. A single chromosomal pac greatly increases transduction of downstream markers without decreasing phage yields; 3.5 × as much total chromosomal DNA is packaged. Additional insertions decrease phage yield by > 90% and also decrease phage DNA synthesis, although less dramatically. Packaging of chromosomal markers near to and downstream of each inserted pac site is, at the same time, increased by greater than 10 fold. Transduction of markers near an inserted pac site can be increased by over 1000-fold, potentially allowing identification of ...
Journal of Molecular Biology, 1972
The host He&C recombination pathway is inefficient for point mutants of phage X dofcrtivc in the viral general recombination pathway. This low level of X recombination can bc increased substantially by the presence of an additional point mut.ation in the gam gene of h or by the presence of a pathway of bacterial rccomhinntion alternative to the RAcBC pathway. Wo suggest that tho gam gene of A codas for a protein (y-protein) which provides for a specific inhibition of the RecBC recombination pathway.
Attachment and detachment of bacteriophage λ DNA in lysogenization and induction
Journal of Molecular Biology, 1968
The experiment reported here traces the fate of bacteriophage h DNA during lysogenization of Escherichicc coli and during subsequent induction of the lysogenized bacteria. Bacteriophage labeled with heavy isotopes and with a host-induced modification property were allowed to infect Hfr H male bacteria under conditions favoring lysogenization. The lysogenized males were mixed with female bacteria, whereupon prophages transferred to the females underwent zygotic induction yielding a progeny of free bacteriophages. Density-gradient analysis and assays on appropriate indicator bacteria showed that a certain proportion of the phages contained host-modified, isotopically labeled DNA chains. This result shows that, during lysogenization of E. coli with bacteriophage h, at least one of the two polynucleotide chains of an infecting phage chromosome can become attached to the bacterial chromosome as prophage and, upon induction, can be detached and recovered intact in a free phage.