Bacteriophage SP6 Is Closely Related to Phages K1-5, K5, and K1E but Encodes a Tail Protein Very Similar to That of the Distantly Related P22 (original) (raw)
Related papers
Journal of Virology, 2001
A virulent double-stranded DNA bacteriophage, ΦK1-5, has been isolated and found to be capable of infecting Escherichia coli strains that possess either the K1 or the K5 polysaccharide capsule. Electron micrographs show that the virion consists of a small icosohedral head with short tail spikes, similar to members of the Podoviridae family. DNA sequence analysis of the region encoding the tail fiber protein showed two open reading frames encoding previously characterized hydrolytic phage tail fiber proteins. The first is the K5 lyase protein gene of ΦK5, which allows this phage to specifically infect K5 E. coli strains. A second open reading frame encodes a protein almost identical in amino acid sequence to the N -acetylneuraminidase (endosialidase) protein of ΦK1E, which allows this phage to specifically infect K1 strains of E. coli . We provide experimental evidence that mature phage particles contain both tail fiber proteins, and mutational analysis indicates that each protein ca...
Journal of Bacteriology, 1992
We have determined the DNA sequence of the bacteriophage P2 tail genes G and H, which code for polypeptides of 175 and 669 residues, respectively. Gene H probably codes for the distal part of the P2 tail fiber, since the deduced sequence of its product contains regions similar to tail fiber proteins from phages Mu, P1, lambda, K3, and T2. The similarities of the carboxy-terminal portions of the P2, Mu, ann P1 tail fiber proteins may explain the observation that these phages in general have the same host range. The P2 H gene product is similar to the products of both lambda open reading frame (ORF) 401 (stf, side tail fiber) and its downstream ORF, ORF 314. If 1 bp is inserted near the end of ORF 401, this reading frame becomes fused with ORF 314, creating an ORF that may represent the complete stf gene that encodes a 774-amino-acid-long side tail fiber protein. Thus, a frameshift mutation seems to be present in the common laboratory strain of lambda. Gene G of P2 probably codes for ...
Journal of Molecular Biology, 1989
Two plasmid systems, containing the easily assayable galK and 1acZ functions, were employed to study the regulation of the bacteriophage Pl tail-fibre and dar operons. Various PI DNA fragments carrying either the 5' end of 2ydA (the 1st gene in the dar operon) or the tail-fibre gene 19 precede the promoterless coding region of galK or were fused, in-frame, to the 1acZ gene. In the presence of an induced Pl prophage, GalK and LacZ activities were both detected after a 20 to 30 minute lag period, indicating that the dar and tail-fibre operons are expressed from positively regulated, late promoters. The corresponding DNA region of the closely related p15B plasmid exhibits comparable promoter properties. Deletion analysis mapped the promoter of a gene 19-&Z fusion to a DNA region upstream from gene R, an open reading frame that precedes the coding frame of gene 19. The tail-fibre gene thus forms the second gene in a three gene operon (genes R, 19 (S) and U). Sequence comparison between this promoter region, upstream sequences of the 1ydA gene and the corresponding portions of the p15B genome allowed the identification of a highly conserved 38 base-pair sequence, which most likely represents a Pl-specific late promoter. This was confirmed by 5' mapping of Pl mRNA. Transcription of both the tail-fibre and dar operons is initiated at sites five and six base-pairs, respectively, downstream from the first conserved nucleotide of this sequence. The conserved motif consists of a standard Escherichia coli -10 region followed by a nine base-pair palindromic sequence located centrally about position -22.
Journal of Bacteriology, 2005
Bacteriophage K1F specifically infects Escherichia coli strains that produce the K1 polysaccharide capsule. Like several other K1 capsule-specific phages, K1F encodes an endo-neuraminidase (endosialidase) that is part of the tail structure which allows the phage to recognize and degrade the polysaccharide capsule. The complete nucleotide sequence of the K1F genome reveals that it is closely related to bacteriophage T7 in both genome organization and sequence similarity. The most striking difference between the two phages is that K1F encodes the endosialidase in the analogous position to the T7 tail fiber gene. This is in contrast with bacteriophage K1-5, another K1-specific phage, which encodes a very similar endosialidase which is part of a tail gene “module” at the end of the phage genome. It appears that diverse phages have acquired endosialidase genes by horizontal gene transfer and that these genes or gene products have adapted to different genome and virion architectures.
Fine Structure Genetic and Physical Map of the Phage P22 Tail Protein Gene
Bacteriophage P22 which are incapable of making functional tail protein can be propagated by the addition of purified mature tail protein trimers to either liquid or solidified medium. This unique in vitro complementation condition has allowed us to isolate 74 absolute lethal tail protein mutants of P22 after hydroxylamine mutagenesis. These phage mutants have an absolute requirement for purified P22 tail protein to be present in a soft agar overlay in order to form plaques and do not grow on any nonsense suppressing strains of Salmonella typhimurium. In order to genetically map and physically locate these mutations we have constructed two complementary sets of fine structure deletion mapping strains using a collection of Tnl insertions in gene 9, the structural gene for the tail protein. Fourteen bacteriophage P22 strains carrying unique Tnl transposon insertions (Ap phage) in gene 9 have been crossed with Ap phage carrying Tnl insertions in gene 20. Phage carrying deletions that a...
Genomic Analysis of Bacteriophages SP6 and K1-5, an Estranged Subgroup of the T7 Supergroup
Journal of Molecular Biology, 2004
We have determined the genome sequences of two closely related lytic bacteriophages, SP6 and K1-5, which infect Salmonella typhimurium LT2 and Escherichia coli serotypes K1 and K5, respectively. The genome organization of these phages is almost identical with the notable exception of the tail fiber genes that confer the different host specificities. The two phages have diverged extensively at the nucleotide level but they are still more closely related to each other than either is to any other phage currently characterized. The SP6 and K1-5 genomes contain, respectively, 43,769 bp and 44,385 bp, with 174 bp and 234 bp direct terminal repeats. About half of the 105 putative open reading frames in the two genomes combined show no significant similarity to database proteins with a known or predicted function that is obviously beneficial for growth of a bacteriophage. The overall genome organization of SP6 and K1-5 is comparable to that of the T7 group of phages, although the specific order of genes coding for DNA metabolism functions has not been conserved. Low levels of nucleotide similarity between genomes in the T7 and SP6 groups suggest that they diverged a long time ago but, on the basis of this conservation of genome organization, they are expected to have retained similar developmental strategies.
Genomic analysis of bacteriophage ε34 of Salmonella enterica serovar Anatum (15+)
BMC Microbiology
Abstract Background The presence of prophages has been an important variable in genetic exchange and divergence in most bacteria. This study reports the determination of the genomic sequence of Salmonella phage ε34, a temperate bacteriophage that was important in the early study of prophages that modify their hosts' cell surface and is of a type (P22-like) that is common in Salmonella genomes. Results The sequence shows that ε34 is a mosaically related member of the P22 branch of the lambdoid phages. Its sequence is compared with the known P22-like phages and several related but previously unanalyzed prophage sequences in reported bacterial genome sequences. Conclusion These comparisons indicate that there has been little if any genetic exchange within the procapsid assembly gene cluster with P22-like E. coli/Shigella phages that are have orthologous but divergent genes in this region. Presumably this observation reflects the fact that virion assembly proteins interact intimatel...
Scientific Reports
Salmonella enterica serovar Typhimurium is a foodborne pathogen causing occasional outbreaks of enteric infections in humans. Salmonella has one of the largest pools of temperate phages in its genome that possess evolutionary significance for pathogen. In this study, we characterized a novel temperate phage Salmonella phage BIS20 (BIS20) with unique tail fiber genes. It belongs to the subfamily Peduovirinae genus Eganvirus and infects Salmonella Typhimurium strain (SE-BS17; Acc. NO MZ503545) of poultry origin. Phage BIS20 was viable only at biological pH and temperature ranges (pH7 and 37 °C). Despite being temperate BIS20 significantly slowed down the growth of host strain for 24 h as compared to control (P < 0.009). Phage BIS20 features 29,477-base pair (bp) linear DNA genome with 53% GC content and encodes for 37 putative ORFs. These ORFs have mosaic arrangement as indicated by its ORF similarity to various phages and prophages in NCBI. Genome analysis indicates its similarity...
Organization of the bacteriophage P1 tail-fibre operon
Gene, 1989
The revised sequence of a bacteriophage Pl DNA fragment containing the 5' end of the tail-libre gene, gene 19, revealed that this gene is closely preceded by another open reading frame (ORF) of 432 bp. We have designated this ORF as gene R. The tail-fibre gene and gene R are transcriptionally and translationally coupled. Thus, the tail-fibre operon of bacteriophage Pl consists of three genes: gene R, gene 19 (or gene S) and gene U. 0378-I 119/89/$03.50 0 1989 Elsevier Science Publishers B.V. (Biomedical Division)
Genomic analysis of bacteriophage epsilon34 of Salmonella enterica serovar Anatum (15+)
BMC Microbiology, 2008
The presence of prophages has been an important variable in genetic exchange and divergence in most bacteria. This study reports the determination of the genomic sequence of Salmonella phage ε 34 , a temperate bacteriophage that was important in the early study of prophages that modify their hosts' cell surface and is of a type (P22-like) that is common in Salmonella genomes.