Order of Injection of T7 Bacteriophage DNA

Pao, Chia-Chu; Speyer, Joseph F.

doi:10.1128/jvi.11.6.1024-1026.1973

Cited by 38 publications

(15 citation statements)

References 13 publications

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“…Analysis of the progeny of alkylated phages showed that a large number of headlike particles were produced during infection. These particles resemble the proheads and empty heads found by Roeder and Sadowski (21) in extracts from cells infected by wild-type phage and various amber mutants; however, none of the tubular or spiral structures observed by Ackermann and Poty (1) in wild-type phage progeny, and produced at high frequency by mutants in genes 8, 14, 15, and 16 (21), were seen. The predominance of proheads in our experiments with alkylated phage may be due to either the lack of gene 19 function or the great delay in DNA synthesis.…”

Section: Resultssupporting

confidence: 63%

“…Karska-Wysocki et al (11) have shown that, after alkylation by methyl methane sulfonate or ethyl methane sulfonate, T7 phage injects only a part of its DNA into the bacterial cell. Since T7 phage injects its DNA in a unique direction, starting from the genetic left end (9,10,16), this leads to the preferential presence of early, as opposed to late, genes within the infected cell (10). In addition, the expression of those genes located towards the left end of the phage genome is enhanced by DNA replication (9).…”

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confidence: 99%

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Biological consequences of infection of Escherichia coli B by alkylated T7 bacteriophage

Karska-Wysocki¹,

Mamet‐Bratley²

1981

J Bacteriol

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Alkylation of T7 bacteriophage considerably delayed phage development and reduced the phage's killing action on host cells. Only a small fraction of infected cells produced phage. For these phages, the latent period was markedly prolonged but the burst was equivalent to or only slightly lower than that of untreated phage. In the progeny of alkylated phage, there was an increase in the fraction of defective particles as well as a change in their morphology. These data show that infection with alkylated T7 bacteriophage is to a large degree abortive; hence, biological consequences of this infection are very different from those characteristic of a nornal virus infection. T7 bacteriophage is inactivated by monofunctional alkylating agents (14,28). While the nature of the chemical lesions introduced into T7 phage DNA by these agents is well documented (29), the exact biological mechanism of phage inactivation by these agents is far from clear. One known consequence of phage alkylation is defective DNA injection. have shown that, after alkylation by methyl methane sulfonate or ethyl methane sulfonate, T7 phage injects only a part of its DNA into the bacterial cell. Since T7 phage injects its DNA in a unique direction, starting from the genetic left end (9, 10, 16), this leads to the preferential presence of early, as opposed to late, genes within the infected cell (10). In addition, the expression of those genes located towards the left end of the phage genome is enhanced by DNA replication (9).We have analyzed the growth cycle of alkylated T7 phage to detect changes in the infective process which occur when the phage DNA contains chemical lesions. We have also examined progeny phage to determine whether their intracellular development and final mature form are equivalent to those observed for untreated phage. These studies are a necessary prerequisite for detailed analysis, at the molecular level, of changes in the various steps in phage replication caused by alkylation of phage. MATERIALS AND METHODSStrains. Wild-type Escherichia coli B came from the collection of P. Fredericq; wild-type T7 phage came from the collection of F. W. Studier. Bacteria and phage were grown and assayed according to previously described techniques (10, 25).Media. Solid and liquid growth media used in most experiments contained T-broth (25) supplemented with 1 mM MgSO4 (12). For experiments involving measurement of DNA synthesis and of 3P leakage, and in certain cases of electron microscopic analysis, the semisynthetic minimal medium described by Thomas and Abelson (27) was used. Chemicals. Methyl methane sulfonate was purchased from Eastman Kodak Co.; [methyl-3H]thymidine, 6.7 Ci/mmol, and [3P]orthophosphoric acid, carrier-free, were purchased from New England Nuclear Corp.Alkylation. Purified T7 phage was used in all alkylation experiments. For most of the work described here, purification was carried out as described by Dussault et al. (5); for some of the one-step growth experiments, phage was purified according to Yamamoto et al. (30)...

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Section: Resultssupporting

confidence: 63%

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confidence: 99%

Biological consequences of infection of Escherichia coli B by alkylated T7 bacteriophage

Karska-Wysocki¹,

Mamet‐Bratley²

1981

J Bacteriol

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“…Finally, it is suggested that the ter system can attack and cut a single cos site without requiring, for its catalytic action, the alignment oftwo such substrates as proposed in certain models (103, 345). Vectorial packaging explains the asymmetric disposition of chromosomes within the finished heads of X (27,60,118,332), as well as that of other phages (60,116,201,229,269,288,289,296).…”

Section: Phage Xmentioning

confidence: 99%

Head morphogenesis of complex double-stranded deoxyribonucleic acid bacteriophages.

Murialdo¹,

Becker²

1978

Microbiological Reviews

162

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“…If NUV inactivated T7 by preventing adsorption to the bacterial host, the decrease in recombination frequency should be independent with respect to the genetic position of the "rescued" amber mutant. However, if adsorption was successful and NUV interfered with injection, the decrease in recombination would depend on the map position of the rescued amber mutant, since T7 injects its DNA linearly in a single direction and with a unique starting point (8,10). This results in a T7 genetic map-dependent effect, with the decrease in recombination frequency lower in early than in late genes.…”

Section: Resultsmentioning

confidence: 99%

Alteration of bacteriophage attachment capacity by near-UV irradiation

Hartman¹,

Einsenstark²

1982

J Virol

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Near-UV (NUV) (300 to 400 nm) and far-UV (FUV) (254 nm) radiations damage bacteriophage by different mechanisms. Host cell reactivation, Weigle reactivation, and multiplicity reactivation were observed upon FUV, but not upon NUV irradiation. Also, the number of his' recombinants increased with P22 bacteriophage transduction in Salmonella typhimurium after FUV, but not after NUV irradiation. This loss of reactivation and recombination after NUV irradiation was not necessarily due to host incapability to repair phage damage. Instead, the phage genome failed to enter the host cell after NUV irradiation. In the case of NUVirradiated T7 phage, this was determined by genetic crosses with amber mutants, which demonstrated that either "all" or "none" of a T7 genome entered the Escherichia coli cell after NUV treatment. Further studies with radioactively labeled phage indicated that irradiated phage failed to adsorb to host cells. This damage by NUV was compared with the protein-DNA cross-link observed previously, when phage particles were irradiated with NUV in the presence of H202. H202 (in nonlethal concentration) acts synergistically with NUV so that equivalent phage inactivation is achieved by much lower irradiation doses.

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Order of Injection of T7 Bacteriophage DNA

Cited by 38 publications

References 13 publications

Biological consequences of infection of Escherichia coli B by alkylated T7 bacteriophage

Biological consequences of infection of Escherichia coli B by alkylated T7 bacteriophage

Head morphogenesis of complex double-stranded deoxyribonucleic acid bacteriophages.

Alteration of bacteriophage attachment capacity by near-UV irradiation

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