Phage genes involved in the formation of generalized transducing particles in Salmonella-phage P22

Raj, A. Sudharsan; Raj, Atul; Schmieger, Horst

doi:10.1007/bf00264784

Cited by 58 publications

(24 citation statements)

References 7 publications

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“…Concatemer DNA is produced by rolling circle replication of P22 DNA circularized by homologous recombination (10). DNA packaging initiates at a particular site (pac) located within gene 3 (11)(12)(13)(14)(15)(16) that encodes S-terminase. Here the nuclease domain of L-terminase breaks the DNA backbone at several points (known as "series initiation cleavages"), generating a DNA end that is inserted into the procapsid, unidirectionally from the initiation cleavage point (10).…”

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confidence: 99%

Structure of P22 Headful Packaging Nuclease

Roy

Cingolani

2012

Journal of Biological Chemistry

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Background:The headful nuclease is essential for genome processing during viral DNA packaging. Results: The crystal structure of P22 nuclease reveals a seven-stranded ␤-sheet core with two magnesium ions poised for catalysis. Conclusion: P22 headful nuclease is active only in the context of the large terminase. Significance: The C-terminal headful nuclease is activated by intramolecular cross-talk with the N-terminal ATPase domain.

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confidence: 99%

Structure of P22 Headful Packaging Nuclease

Roy

Cingolani

2012

Journal of Biological Chemistry

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“…This subpopulation of particles contains most if not all regions of the host chromosome, although in widely varying concentrations (29). It is believed, although this has not been absolutely proven, that host DNA is substituted for viral DNA owing to the presence of pseudo "pac" sites present on the host chromosome (7,18,26,32). Since its discovery (21), P22 generalized transduction has played a pivotal and indispensable role in the genetics of salmonellae (28).…”

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confidence: 99%

Rapid mapping in Salmonella typhimurium with Mud-P22 prophages

1992

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A new method for mapping mutations in the Salmonella typhimurium chromosome is described and applied to the localization of novel regulatory mutations affecting expression of the nirB (nitrite reductase) gene. The mapping technique'is also illustrated by the mapping of mutations in genes affecting carbohydrate catabolism and biosynthetic pathways. The new mapping method involves use of the hybrid phage MudP and MudQ (together referred to as Mud-P22), originally constructed by Youderian et al. (Genetics 118:581-592, 1988). This report describes a set of Mud-P22 lysogens, each member of the set containing a different Mud-P22 insertion. The insertions are scattered along the entire Salmonella genome. These lysogens, when induced by mitomycin C, generate transducing lysates that are enriched (45-to 1,400-fold over the background, generalized transducing particle population) for transducing particles containing bacterial DNA that flanks one side of the insertion. We demonstrate that within the set of lysogens there can be found at least one Mud-P22 insertion that enriches for any particular region of the Salmonella chromosome and that, therefore, all regions of the chromosome are discretely enriched and represented by the collection as a whole. We describe a technique that allows the rapid and facile determination of which lysate contains enriched sequences for the repair of a mutant locus, thereby allowing the determination of the map position of the locus. This technique is applicable to those mutations for which the wild-type allele is selectable. We also describe a procedure whereby any TnlO insertion can be mapped by selecting for the loss of Tetr. Transduction refers to the transfer of genetic information (DNA) from one bacterium to another via a phage particle. Generalized transduction refers to the ability of the transducing mechanism to transfer information from all parts of the donor genome. P22 is one of several phage that mediate generalized transduction in salmonellae (21). The mechanism whereby P22 mediates generalized transduction is understood at a general level, although some of the specific molecular details require further elucidation (for a review of P22 molecular genetics, see references 25 and 31).P22 packages its genome by processive packaging of 43. 4-kb (+0.75 kb [3]) fragments derived from a doublestranded, linear, concatemeric DNA molecule. Gene 3 is believed to code for a nuclease which recognizes a specific nucleotide sequence within the gene 3 coding sequence called the pac site (4,20,26). Once the pac site is recognized, a cut is made near the pac site (3, 17) and unidirectional packaging of the concatemer into phage heads begins. The direction of packaging is from gene 3, towards the late genes and the immunity I region. Continuous filling of heads from one concatemer may continue for 3 to 8 headfuls, depending on the genotype of the virus (1).Lysates made from wild-type P22 are found to contain small amounts of host rather than viral DNA (approximately 3% of the plaque-forming particl...

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“…An amber mutant of endolysin, P22am7, found in the homologous region, was also used. In addition, one amber mutant outside the homologous region, P22am3 in gene 3 (Raj et al, 1974), was studied.…”

Section: Methodsmentioning

confidence: 99%

Analysis of Proteins Induced by the Salmonella typhimurium Phage P221, a Hybrid between Serologically and Morphologically Unrelated Phages P22 and Fels 1

Droffner¹,

Yamamoto

1982

Journal of General Virology

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SUMMARYThe Salmonella phage P221 is a hybrid between the morphologically and serologically unrelated Salmonella phages P22 and Fels 1. P221 carries about 30% of P22 DNA containing a number of the early genes. Head and tail proteins are morphologically and serologically indistinguishable from those of Fels 1. The early proteins synthesized in Salmonella typhimurium strain Q 1 after P221 infection were pulse-labelled with 35S and analysed by gel electrophoresis and autoradiography. These P221 early proteins were compared with early P22 proteins in an effort to detect proteins specified by the homologous region between P22 and P221. This analysis showed that nine P221 protein bands correspond to P22 protein bands. Seven of these protein bands appeared early, about 6 min after infection, and two additional protein bands appeared about 18 min after infection. The origin of these nine protein bands was also determined by protein synthesis patterns of P22 amber mutants. A large number of previously isolated P22 amber mutants were subdivided as to their location within the homologous or non-homologous region by complementation and marker rescue experiments. Four P22 amber mutants located within the homologous region were chosen for analysis of their early proteins. When the non-permissive host Q1 was infected with a P22 amber mutant in gene 24 (the gene which initiates the transcription of the P22 phage genome) no phage protein bands were observed. Similarly, when two P22 amber mutants located in gene 12 and gene 23 infected the non-permissive host Q1 no phage protein bands were detected. Mutants of the gene for endolysin showed that one specific protein band was lacking in the non-permissive host. When the amber suppressor host Qsu + was infected with any of the above amber mutants all protein bands were found. By the use of an amber mutant in gene 3 of the P22 late gene region located outside the P22-P221 homologous region, we showed that mutations in the non-homologous region did not affect the synthesis of these nine proteins. The genetic origin of proteins found in mature P221 particles was determined by subjecting proteins of purified P221, P22 and Fels 1 phage particles to analysis by SDS-gel electrophoresis. It was concluded that P221 and Fels 1 share the same head, tail and internal proteins in mature phage particles, whereas none of the protein components of these mature phage particles is the same as those of P22 particles.

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Phage genes involved in the formation of generalized transducing particles in Salmonella-phage P22

Cited by 58 publications

References 7 publications

Structure of P22 Headful Packaging Nuclease

Structure of P22 Headful Packaging Nuclease

Rapid mapping in Salmonella typhimurium with Mud-P22 prophages

Analysis of Proteins Induced by the Salmonella typhimurium Phage P221, a Hybrid between Serologically and Morphologically Unrelated Phages P22 and Fels 1

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