Mechanisms of genome propagation and helper exploitation by satellite phage P4.

Lindqvist, Björn H.; Dehò, Gianni; Calendar, Richard

doi:10.1128/mmbr.57.3.683-702.1993

Cited by 114 publications

(79 citation statements)

References 156 publications

(310 reference statements)

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“…are highlighted in red. [Color figure can be viewed at wileyonlinelibrary.com] genes of P2 for its propagation (Six and Klug, 1973;Lindqvist et al, 1993;Briani et al, 2001). In this study, our analysis demonstrated that integrases near the ssrA locus in Shewanella can be divided into at least two families, P4 and P2.…”

Section: Discussionmentioning

confidence: 52%

Symbiosis of a P2‐family phage and deep‐sea Shewanella putrefaciens

Liu

Tang

Zhang

et al. 2019

Environmental Microbiology

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Summary Almost all bacterial genomes harbour prophages, yet it remains unknown why prophages integrate into tRNA‐related genes. Approximately 1/3 of Shewanella isolates harbour a prophage at the tmRNA (ssrA) gene. Here, we discovered a P2‐family prophage integrated at the 3′‐end of ssrA in the deep‐sea bacterium S. putrefaciens. We found that ~0.1% of host cells are lysed to release P2 constitutively during host growth. P2 phage production is induced by a prophage‐encoded Rep protein and its excision is induced by the Cox protein. We also found that P2 genome excision leads to the disruption of wobble base pairing of SsrA due to site‐specific recombination, thus disrupting the trans‐translation function of SsrA. We further demonstrated that P2 excision greatly hinders growth in seawater medium and inhibits biofilm formation. Complementation with a functional SsrA in the P2‐excised strain completely restores the growth defects in seawater medium and partially restores biofilm formation. Additionally, we found that products of the P2 genes also increase biofilm formation. Taken together, this study illustrates a symbiotic relationship between P2 and its marine host, thus providing multiple benefits for both sides when a phage is integrated but suffers from reduced fitness when the prophage is excised.

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Section: Discussionmentioning

confidence: 52%

Symbiosis of a P2‐family phage and deep‐sea Shewanella putrefaciens

Liu

Tang

Zhang

et al. 2019

Environmental Microbiology

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“…More recently, a role of uncharged tRNA was described in .qtabilig~ng ~pecific RNA anti-termination structures in B. subtili~ [55]. The RNA-mediated transcriptional regulation of phages P1 and P4, discussed in this issue [56,57,63,64], are particularly striking examl~les of structural roles of complementary RNA segments interacting in alternative pairings to regulate l~hysiological processes. The function of wedge RIqA in initiation of phage T4 DNA replication is a novel variation on this theme.…”

Section: Z2 Functional Aspects Of Secondary Nucleic Acid Structuresmentioning

confidence: 99%

Multiple initiation mechanisms adapt phage T4 DNA replication to physiological changes during T4's development

Mosig¹

1995

FEMS Microbiology Reviews

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We summarize the evidence for multiple pathways to initiate phage T4 DNA replication. In any infecting chromosome, leading DNA strands can be primed from pre-replicative transcripts, independent of primase activity, at one of several origins. Within each origin region, there are multiple RNA-DNA transition sites. However, the priming potential at each single site is very low. Our results suggest that origin transcripts can become primers for leading strand DNA synthesis without being processed, but that a promoter-proximal segment of each origin transcript plays an important structural role, as a proposed wedge, in the transition from RNA to DNA synthesis. Two recombination-dependent pathways render subsequent phage T4 DNA replication independent of transcription. The first of these requires proteins that are synthesized during the pre-replicative phase of infection. It is active as soon as the first growing points, initiated at origins, have reached a chromosomal end. The other one requires at least one late protein: endonuclease VII, a resolvase that cuts recombinational junctions. The latter pathway can bypass primase deficiencies by allowing retrograde DNA synthesis without Okazaki pieces. We discuss the integration of these multiple and redundant pathways into the developmental program of T4. Competition between these initiation mechanisms and with other DNA transactions allows for integration of replication controls with transcription, recombination and packaging of the DNA.

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“…P1 C4 RNA exhibits complementarity to both upstream and downstream sequences in the leader transcript. The downstream complementary sequence covers the icd translation initiation signal [15,31].…”

Section: Comparison With Retronphage @R73 and Phage P1mentioning

confidence: 99%

“…In order to replicate, P4 requires the product of gene ~, a protein endowed with origin recognition, primase and helicase activities [11-131. Early studies of P4 gene expression showed that the production of oe protein is modulated during the P4 life cycle [14]. This review will be focused on the multiple controls of o~ gene expression (.other aspects of I)4 and its helper P2 biology have been recently reviewed; [15,16]). a is the last gene of a polycistronie operon, transcribed from either of two promoters.…”

Section: Introductionmentioning

confidence: 99%

Multiple regulatory mechanisms controlling phage-plasmid P4 propagation

Ghisotti

1995

FEMS Microbiology Reviews

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Bacteriophage 1'4 autonomous replication may result in the lyric cycle or in plasmid maintenance, depending, respectively, on the presence or absence of the helper phage P2 genome in the Escherichia coil host cell. Alternatively, P4 may lysogenize the bacterial host and be mainta/ned in an immune-integrated condition. A key step in the choice between the lytic/plasmid vs. the lysogenic condition is the regulation of 1'4 t~ eperon. This operon may be transcribed from two promoters, PL~ and PLL, and encodes both immunity (promoter proximal)and replication (promoter distal) functions. PLE is a constitutive promoter and transcription of the downstream replication genes is regulated by transcription termination. The trans-acting immunity factor that controls premature transcription termination is a short RNA encoded in the PtE proximal part of the operon. Expression of the replication functions in the lytic/plasmid condition is achieved by activation of the PLL promoter. Transcription from PLt is insensitive to the termination mechanism that acts on transcription starting from PLE" PLL is also negatively regulated by 1'4 off88, the first gene downstream of l%L. An additional control on P4 DNA replication is exerted by the P4 car gene product.

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Mechanisms of genome propagation and helper exploitation by satellite phage P4.

Cited by 114 publications

References 156 publications

Symbiosis of a P2‐family phage and deep‐sea Shewanella putrefaciens

Symbiosis of a P2‐family phage and deep‐sea Shewanella putrefaciens

Multiple initiation mechanisms adapt phage T4 DNA replication to physiological changes during T4's development

Multiple regulatory mechanisms controlling phage-plasmid P4 propagation

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