P2 phage amber mutants: Characterization by use of a polarity supressor

doi:10.1016/0042-6822(71)90071-7

Virology

Volume 46, Issue 3, December 1971, Pages 691-702

https://doi.org/10.1016/0042-6822(71)90071-7 Get rights and content

Abstract

Seventy amber mutants of temperate phage P2 have been characterized, using an Escherichia coli strain which suppresses polarity. Two new genes involved in tail synthesis were defined. The eighteen known P2 late genes can be divided into four transcription units. One of these is transcribed in the opposite direction from the other three. The largest transcription unit contains four head genes, a gene involved in cell lysis, and two tail genes.

References (23)

R.K. Appleyard et al.
Mutation to extended host range and the occurrence of phenotypic mixing in the temperate coliphage lambda
Virology
(1956)
J. Beckwith
Restoration of operon activity by suppressors
Biochim. Biophys. Acta
(1963)
G. Bertani et al.
Inheritance of prophage P2 in bacterial crosses
Virology
(1958)
L.E. Bertani
The effect of the inhibition of protein synthesis on the establishment of lysogeny
Virology
(1957)
L.E. Bertani
Host-dependent induction of phage mutants and lysogenization
Virology
(1960)
G. Lindahl
Genetic map of bacteriophage P2
Virology
(1969)
G. Lindahl
Bacteriophage P2: Replication of the chromosome requires a protein which acts only on the genome that coded for it
Virology
(1970)
G. Lindahl
On the control of transcription in bacteriophage P2
Virology
(1971)
G. Sironi
Mutants of Escherichia coli unable to be lysogenized by the temperate bacteriophage P2
Virology
(1969)
G. Bertani
Studies of lysogenesis. I. The mode of phage liberation by lysogenic E. coli.
J. Bacteriol.
(1951)

G. Bertani et al.

Host-controlled variation in bacterial viruses

J. Bacteriol.

(1953)

Cited by (89)

Dimerization of bacteriophage P2 integrase is not required for binding to its DNA target but for its biological activity
2005, Gene
Coliphage P2 integrates into the host chromosome upon lysogenization via site-specific recombination mediated by the phage integrase (Int). P2 integrase belongs to the tyrosine family of recombinases. In this work, it is shown that P2 integrase forms dimers but not oligomers in the absence of its DNA target. Furthermore, the C-terminal end of the protein and amino acid (aa) E197 have been found to be involved in dimerization. Amino acid E197 is located in a conserved region of the tyrosine recombinases that has not previously been implicated in dimerization. The dimerization deficient mutants were unaffected in binding to its phage attachment site (attP) substrate, but had a reduced ability to complement an int-defective prophage.
In vivo and in vitro evidence for an anti-rho activity induced by the phage P4 polarity suppressor protein Psu
1997, Virology
The polarity suppression (Psu) protein of bacteriophage P4 causes suppression of transcriptional polarity inEscherichia coliby overcoming Rho termination factor activity. Two newpsumutants defective in polarity suppression are described. Thepsu5mutation deletes codons 95–98 from about the middle of the gene, and the mutant protein is inactive. Thepsu6mutation changes Phe169 to Val and encodes a temperature-sensitive protein. Constitutive overexpression ofpsu⁺from a plasmid prevents colony formation, but overexpression of mutant genes (psu5, psu6) does not, suggesting that Psu disturbs essential host function(s). Rho protein synthesis is enhanced several-fold in cells containing wild-type Psu, due to readthrough at therhoattenuator, while the physical stability of Rho is maintained. As a consequence, Psu-producing cells accumulate significantly more Rho than normal cells, reminiscent of termination-defectiverhomutants. The polarity suppression activity induced by Psu is demonstratedin vitroby the efficient readthrough of Rho-dependent terminators λ t_R1and T_IS2during coupled transcription–translation. Purified Rho protein restores termination at T_IS2when added to Psu-containing reactions but NusG does not. The data support the hypothesis that Psu has or elicits an anti-Rho function.
A Rho-dependent transcription termination site regulated by bacteriophage P4 RNA immunity factor
1996, Virology
The genes required for replication of the temperate bacteriophage P4, which are coded by the phage left operon, are expressed from a constitutive promoter (P_LE). In the lysogenic state, repression of the P4 replication genes is achieved by premature transcription termination. The leader region of the left operon encodes all the genetic determinants required for prophage immunity, namely: (i) the P4 immunity factor, a short, stable RNA (CI RNA) that is generated by processing of the leader transcript; (ii) two specific target sequences that exhibit complementarity with the CI RNA. RNA–RNA interactions between the CI RNA and the target sites on the mRNA leader region are essential for transcription termination. To understand how transcription termination is elicited by the P4 immunity mechanism, it is relevant to identify the transcription termination site. This, however, could not be directly inferred from the 3′-end of the transcription products because of the extensive and complex processing and degradation of the leader RNA. In this work, by making use of a tRNA gene as a reporter, we identify the termination site of the immunity transcripts (t_imm). This is a Rho-dependent terminator located within the first translated gene of the left operon and is regulated by P4 immunity. Analysis of the P4 transcription pattern inEscherichia coli rhomutants suggests that termination att_immmay also be important for the efficient processing of the CI RNA.
Bacteriophage P4 capsid-size determination and its relationship to P2 helper interference
1996, Virology
Thesid(sizedetermination) gene product of phage P4 is known to be involved in capsid-size determination. Moreover, the capsid-size determination function interferes with the lytic development of its helper P2, presumably because the helper genome is too large to be packaged into P4-size capsids. In order to study P4-specified helper interference, we cloned thesidgene for expression during phage infection. Even though gpSid restores the capsid-size determination function of asiddefective P4 mutant, we find that gpSid alone is not sufficient to establish full interference of helper P2 phage production. Complete helper interference requires some P4 function in addition to gpSid. Complementation tests show that none of the known P4 genes display this property. We propose that P4 encodes a yet-unidentified function that in concert with gpSid establishes full P2 helper interference at the level of capsid-size determination.
Bacteriophage P2 and P4 morphogenesis: Assembly precedes proteolytic processing of the capsid proteins
1994, Virology
Several of the structural proteins of phage P2 and its satellite P4 undergo proteolytic processing during development of mature phage particles. Here, we report that uncleaved shell protein, gpN, is present in immature capsids of both P2 and P4, showing that assembly precedes processing. This excludes the possibility that processing of gpN is involved in capsid size determination. We also find that N*, the fully processed version of gpN, produced from a plasmid, can assemble into both P2- and P4-sized particles, implying that the amino-terminal end of gpN is not required for assembly initiation nor for the formation of a T = 4 shell. As may be expected for a scaffolding protein, we find that gpO coexists with gpN in immature P2, as well as P4, capsids. This result supports the conclusion that gpO is required for both phages and strongly suggests that the O derivative, h7 (found in mature capsids), results from proteolytic cleavage after gpN/gpO coassembly.
Bacteriophage P2 and P4 assembly: Alternative scaffolding proteins regulate capsid size
1994, Virology
The capsid protein of bacteriophage P2, encoded by the N gene, can assemble into icosahedraf capsids of two possible sizes, with diameters of 60 and 45 nm, respectively. Only the larger capsid is used by P2 itself, but the smaller one is exploited by the satellite phage P4. We have analyzed the assembly products of gpN expressed in vivo from a plasmid, i.e., in the absence of any other phage proteins, and find that gpN alone forms closed shells of both sizes, although with poor efficiency. Coexpressing gpN with gpO, the putative P2 scaffolding protein, increases the efficiency of large particle formation. In contrast, introducing the sid gene by P4 infection stimulates the assembly of small particles. Our results suggest that gpO and gpSid act competitively with respect to capsid size determination. Furthermore, we demonstrate that gpN alone undergoes the normal proteolytic maturation steps, implying that gpN processing is either autocatalytic or mediated by a host enzyme.

View all citing articles on Scopus

View full text

Article preview

Virology

Abstract

References (23)

Mutation to extended host range and the occurrence of phenotypic mixing in the temperate coliphage lambda

Virology

Restoration of operon activity by suppressors

Biochim. Biophys. Acta

Inheritance of prophage P2 in bacterial crosses

Virology

The effect of the inhibition of protein synthesis on the establishment of lysogeny

Virology

Host-dependent induction of phage mutants and lysogenization

Virology

Genetic map of bacteriophage P2

Virology

Bacteriophage P2: Replication of the chromosome requires a protein which acts only on the genome that coded for it

Virology

On the control of transcription in bacteriophage P2

Virology

Mutants of Escherichia coli unable to be lysogenized by the temperate bacteriophage P2

Virology

Studies of lysogenesis. I. The mode of phage liberation by lysogenic E. coli.

J. Bacteriol.

Host-controlled variation in bacterial viruses

J. Bacteriol.

Cited by (89)

Dimerization of bacteriophage P2 integrase is not required for binding to its DNA target but for its biological activity

In vivo and in vitro evidence for an anti-rho activity induced by the phage P4 polarity suppressor protein Psu

A Rho-dependent transcription termination site regulated by bacteriophage P4 RNA immunity factor

Bacteriophage P4 capsid-size determination and its relationship to P2 helper interference

Bacteriophage P2 and P4 morphogenesis: Assembly precedes proteolytic processing of the capsid proteins

Bacteriophage P2 and P4 assembly: Alternative scaffolding proteins regulate capsid size