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Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction.

Bloch S, Nejman-Faleńczyk B, Łoś JM, Barańska S, Łepek K, Felczykowska A, Łoś M, Węgrzyn G, Węgrzyn A - Arch. Microbiol. (2013)

Bottom Line: The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions.No significant effects of an increased copy number of genes located between exo and xis on both efficiency of adsorption on the host cells and lytic development inside the host cell of these bacteriophages were found.We conclude that genes from the exo-xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.

ABSTRACT
The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions. In this report, using bacteriophage λ and Shiga toxin-converting bacteriophage ϕ24Β, we demonstrate that the presence of this region on a multicopy plasmid results in impaired lysogenization of Escherichia coli and delayed, while more effective, induction of prophages following stimulation by various agents (mitomycin C, hydrogen peroxide, UV irradiation). Spontaneous induction of λ and ϕ24Β prophages was also more efficient in bacteria carrying additional copies of the corresponding exo-xis region on plasmids. No significant effects of an increased copy number of genes located between exo and xis on both efficiency of adsorption on the host cells and lytic development inside the host cell of these bacteriophages were found. We conclude that genes from the exo-xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance.

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Related in: MedlinePlus

Comparison between sequences of open reading frames (a) and their putative products (b) from the exo–xis regions (e.x.r.) of bacteriophages λ, ϕ24B and 933W (accession numbers: GI:9626243, GI:307604077, GI:4585377, respectively). aDark arrows with continuous outer border lines represent highly conserved (>70 % sequence identity) genes and open reading frames. Dark arrows with punctuated outer borders represent highly conserved (>70 % sequence identity) open reading frames present in genomes of λ and 933W phages, which are available in the NCBI database but were either uncharacterized or even not mentioned in annotations. The presence of orf73 in the λ exo–xis region was indicated by Sergueev et al. (2002). Light arrows represent genes and open reading frames with low level (<35 %) of identity. The pairwise scores were calculated for every pair of sequences that was aligned using the ClustalW program, but only highly conserved (>70 % sequence identity) homologs of λ orf60a, orf 63, orf61, and orf73 were considered. Pairwise scores represent the number of identities between two compared sequences, divided by the length of the alignment, and shown as a percentage. b ClustalW program was used to align multiple amino acid sequences. Translation of nucleotide sequences of λ orf73 and its 933W homolog were generated on ExPASy, and VIRT12251 and VIRT11373 products were predicted, respectively
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Fig1: Comparison between sequences of open reading frames (a) and their putative products (b) from the exo–xis regions (e.x.r.) of bacteriophages λ, ϕ24B and 933W (accession numbers: GI:9626243, GI:307604077, GI:4585377, respectively). aDark arrows with continuous outer border lines represent highly conserved (>70 % sequence identity) genes and open reading frames. Dark arrows with punctuated outer borders represent highly conserved (>70 % sequence identity) open reading frames present in genomes of λ and 933W phages, which are available in the NCBI database but were either uncharacterized or even not mentioned in annotations. The presence of orf73 in the λ exo–xis region was indicated by Sergueev et al. (2002). Light arrows represent genes and open reading frames with low level (<35 %) of identity. The pairwise scores were calculated for every pair of sequences that was aligned using the ClustalW program, but only highly conserved (>70 % sequence identity) homologs of λ orf60a, orf 63, orf61, and orf73 were considered. Pairwise scores represent the number of identities between two compared sequences, divided by the length of the alignment, and shown as a percentage. b ClustalW program was used to align multiple amino acid sequences. Translation of nucleotide sequences of λ orf73 and its 933W homolog were generated on ExPASy, and VIRT12251 and VIRT11373 products were predicted, respectively

Mentions: The exo–xis region of bacteriophage λ genome, previously described by Sergueev et al. (2002), contains 7 open reading frames, named: orf60a, orf63, orf61, orf73, ea22, ea8.5 and orf55. Comparatively, exo–xis regions of genomes of a couple of the best investigated Stx phages, ϕ24B and 933W, contain additional open reading frames (Fig. 1). We found that four of the identified ORFs are highly conserved among λ and tested Stx phages. Genomes of phages ϕ24B and 933W contain homologs of following phage λ ORFs: orf60a, orf63, orf61, and orf73 which reveal high levels (>70 %) of identity of DNA sequences and amino acid sequences of putative gene products (Fig. 1). Other ORFs shown in Fig. 1 were of low similarity (<35 % of sequence identity at DNA and protein levels).Fig. 1


Genes from the exo-xis region of λ and Shiga toxin-converting bacteriophages influence lysogenization and prophage induction.

Bloch S, Nejman-Faleńczyk B, Łoś JM, Barańska S, Łepek K, Felczykowska A, Łoś M, Węgrzyn G, Węgrzyn A - Arch. Microbiol. (2013)

Comparison between sequences of open reading frames (a) and their putative products (b) from the exo–xis regions (e.x.r.) of bacteriophages λ, ϕ24B and 933W (accession numbers: GI:9626243, GI:307604077, GI:4585377, respectively). aDark arrows with continuous outer border lines represent highly conserved (>70 % sequence identity) genes and open reading frames. Dark arrows with punctuated outer borders represent highly conserved (>70 % sequence identity) open reading frames present in genomes of λ and 933W phages, which are available in the NCBI database but were either uncharacterized or even not mentioned in annotations. The presence of orf73 in the λ exo–xis region was indicated by Sergueev et al. (2002). Light arrows represent genes and open reading frames with low level (<35 %) of identity. The pairwise scores were calculated for every pair of sequences that was aligned using the ClustalW program, but only highly conserved (>70 % sequence identity) homologs of λ orf60a, orf 63, orf61, and orf73 were considered. Pairwise scores represent the number of identities between two compared sequences, divided by the length of the alignment, and shown as a percentage. b ClustalW program was used to align multiple amino acid sequences. Translation of nucleotide sequences of λ orf73 and its 933W homolog were generated on ExPASy, and VIRT12251 and VIRT11373 products were predicted, respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig1: Comparison between sequences of open reading frames (a) and their putative products (b) from the exo–xis regions (e.x.r.) of bacteriophages λ, ϕ24B and 933W (accession numbers: GI:9626243, GI:307604077, GI:4585377, respectively). aDark arrows with continuous outer border lines represent highly conserved (>70 % sequence identity) genes and open reading frames. Dark arrows with punctuated outer borders represent highly conserved (>70 % sequence identity) open reading frames present in genomes of λ and 933W phages, which are available in the NCBI database but were either uncharacterized or even not mentioned in annotations. The presence of orf73 in the λ exo–xis region was indicated by Sergueev et al. (2002). Light arrows represent genes and open reading frames with low level (<35 %) of identity. The pairwise scores were calculated for every pair of sequences that was aligned using the ClustalW program, but only highly conserved (>70 % sequence identity) homologs of λ orf60a, orf 63, orf61, and orf73 were considered. Pairwise scores represent the number of identities between two compared sequences, divided by the length of the alignment, and shown as a percentage. b ClustalW program was used to align multiple amino acid sequences. Translation of nucleotide sequences of λ orf73 and its 933W homolog were generated on ExPASy, and VIRT12251 and VIRT11373 products were predicted, respectively
Mentions: The exo–xis region of bacteriophage λ genome, previously described by Sergueev et al. (2002), contains 7 open reading frames, named: orf60a, orf63, orf61, orf73, ea22, ea8.5 and orf55. Comparatively, exo–xis regions of genomes of a couple of the best investigated Stx phages, ϕ24B and 933W, contain additional open reading frames (Fig. 1). We found that four of the identified ORFs are highly conserved among λ and tested Stx phages. Genomes of phages ϕ24B and 933W contain homologs of following phage λ ORFs: orf60a, orf63, orf61, and orf73 which reveal high levels (>70 %) of identity of DNA sequences and amino acid sequences of putative gene products (Fig. 1). Other ORFs shown in Fig. 1 were of low similarity (<35 % of sequence identity at DNA and protein levels).Fig. 1

Bottom Line: The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions.No significant effects of an increased copy number of genes located between exo and xis on both efficiency of adsorption on the host cells and lytic development inside the host cell of these bacteriophages were found.We conclude that genes from the exo-xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.

ABSTRACT
The exo-xis region, present in genomes of lambdoid bacteriophages, contains highly conserved genes of largely unknown functions. In this report, using bacteriophage λ and Shiga toxin-converting bacteriophage ϕ24Β, we demonstrate that the presence of this region on a multicopy plasmid results in impaired lysogenization of Escherichia coli and delayed, while more effective, induction of prophages following stimulation by various agents (mitomycin C, hydrogen peroxide, UV irradiation). Spontaneous induction of λ and ϕ24Β prophages was also more efficient in bacteria carrying additional copies of the corresponding exo-xis region on plasmids. No significant effects of an increased copy number of genes located between exo and xis on both efficiency of adsorption on the host cells and lytic development inside the host cell of these bacteriophages were found. We conclude that genes from the exo-xis region of lambdoid bacteriophages participate in the regulation of lysogenization and prophage maintenance.

Show MeSH
Related in: MedlinePlus