Suppressors of mutations in the bacteriophage T4 gene coding for both RNA ligase and tail fiber attachment activities

Hall, Dwight H.; Sargent, R. Geoffrey; Trofatter, Kenneth F.; Russell, Darcy L.

doi:10.1128/jvi.36.1.103-108.1980

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…hus mutants grow poorly in the presence of hydroxyurea, while the growth of Rid394 depends on the allelic state of the host rho gene, whose product modulates transcription termination; these traits are considered in Discussion. The locations of most of the t mutations agree with previous mapping studies (11,13,38), except that Rid394 does not sequence to the predicted position (26) and the order of amA3 and amB5, while consistent among all later maps, is reversed from that given in the canonical report (15); the amber mutants may have been reversed when originally archived, or the original mapping may have employed too few mutants to secure the order correctly.…”

Section: Resultssupporting

confidence: 79%

“…Additional sequencing confirmed that none of the three tr mutants contain mutations in the distant rI gene (whose mutations are phenotypically identical to rV mutations). We next sequenced all of the previously mapped t mutants (11,13,26), with the results shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…rho encodes an mRNA termination factor important in T4 replication (36), but the reason for the growth advantage of tRid394 on certain rho mutants remains unclear. Third, suppressors of 63 mutations are often t mutations, and ttsDH634 was selected as a temperature-sensitive example of such a suppressor (13). 63 encodes a protein with both RNA ligase and tail fiber attachment activities, but the mechanism of suppression has not been worked out.…”

Section: Discussionmentioning

confidence: 99%

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Lysis and Lysis Inhibition in Bacteriophage T4: rV Mutations Reside in the Holin t Gene

Dressman

Drake

1999

J Bacteriol

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Upon infecting populations of susceptible host cells, T-even bacteriophages maximize their yield by switching from lysis at about 25 to 35 min at 37°C after infection by a single phage particle to long-delayed lysis (lysis inhibition) under conditions of sequential infection occurring when free phages outnumber host cells. The timing of lysis depends upon gene t and upon one or more rapid-lysis (r) genes whose inactivation prevents lysis inhibition. t encodes a holin that mediates the movement of the T4 endolysin though the inner cell membrane to its target, the cell wall. The rI protein has been proposed to sense superinfection. Of the five reasonably well characterized r genes, only two,rI and rV, are clearly obligatory for lysis inhibition. We show here that rV mutations are alleles oft that probably render the t protein unable to respond to the lysis inhibition signal. The tr alleles cluster in the 5′ third of t and produce a strong r phenotype, whereas conditional-lethal t alleles produce the classical t phenotype (inability to lyse) and other t alleles produce additional, still poorly understood phenotypes. trmutations are dominant to t +, a result that suggests specific ways to probe T4 holin function.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Lysis and Lysis Inhibition in Bacteriophage T4: rV Mutations Reside in the Holin t Gene

Dressman

Drake

1999

J Bacteriol

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“…A65T (5tsDH6318) has been isolated as a pseudo-revertant of the gene 63 − mutant. Gp63 has a function to facilitate tailfiber attachment, and A65T is a bypass mutant of gene 63 deletion (Hall et al 1980). The mechanism of the bypass function is not known.…”

Section: Tail Lysozyme Gp5mentioning

confidence: 99%

Molecular assembly and structure of the bacteriophage T4 tail

et al. 2016

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The tail of bacteriophage T4 undergoes large structural changes upon infection while delivering the phage genome into the host cell. The baseplate is located at the distal end of the contractile tail and plays a central role in transmitting the signal to the tail sheath that the tailfibers have been adsorbed by a host bacterium. This then triggers the sheath contraction. In order to understand the mechanism of assembly and conformational changes of the baseplate upon infection, we have determined the structure of an in vitro assembled baseplate through the three-dimensional reconstruction of cryo-electron microscopy images to a resolution of 3.8 Å from electron micrographs. The atomic structure was fitted to the baseplate structure before and after sheath contraction in order to elucidate the conformational changes that occur after bacteriophage T4 has attached itself to a cell surface. The structure was also used to investigate the protease digestion of the assembly intermediates and the mutation sites of the tail genes, resulting in a number of phenotypes.

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“…There are a number of mutants with distinct phenotypes which have a mutation in gene 5 (4,6,20). All the mutation sites were recently determined by sequencing the genomic DNA from each mutant (15).…”

mentioning

confidence: 99%

The C-Terminal Fragment of the Precursor Tail Lysozyme of Bacteriophage T4 Stays as a Structural Component of the Baseplate after Cleavage

Kanamaru

Gassner

et al. 1999

J Bacteriol

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Tail-associated lysozyme of bacteriophage T4 (tail lysozyme), the product of gene 5 (gp 5), is an essential structural component of the hub of the phage baseplate. It is synthesized as a 63-kDa precursor, which later cleaves to form mature gp 5 with a molecular weight of 43,000. To elucidate the role of the C-terminal region of the precursor protein, gene 5 was cloned and overexpressed and the product was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, analytical ultracentrifugation, and circular dichroism. It was shown that the precursor protein tends to be cleaved into two fragments during expression and that the cleavage site is close to or perhaps identical to the cleavage site in the infected cell. The two fragments, however, remained associated. The lysozyme activity of the precursor or the nicked protein is about 10% of that of mature gp 5. Both the N-terminal mature tail lysozyme and the C-terminal fragment were then isolated and characterized by far-UV circular dichroism and analytical ultracentrifugation. The latter remained trimeric after dissociation from the N-terminal fragment and is rich in β-structure as predicted by an empirical method. To trace the fate of the C-terminal fragment, antiserum was raised against a synthesized peptide of the last 12 C-terminal residues. Surprisingly, the C-terminal fragment was found in the tail and the phage particle by immunoblotting. The significance of this finding is discussed in relation to the molecular assembly and infection process.

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Suppressors of mutations in the bacteriophage T4 gene coding for both RNA ligase and tail fiber attachment activities

Cited by 9 publications

References 20 publications

Lysis and Lysis Inhibition in Bacteriophage T4: rV Mutations Reside in the Holin t Gene

Lysis and Lysis Inhibition in Bacteriophage T4: rV Mutations Reside in the Holin t Gene

Molecular assembly and structure of the bacteriophage T4 tail

The C-Terminal Fragment of the Precursor Tail Lysozyme of Bacteriophage T4 Stays as a Structural Component of the Baseplate after Cleavage

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