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The CJIE1 prophage of Campylobacter jejuni affects protein expression in growth media with and without bile salts.

ABSTRACT: BACKGROUND: The presence of Campylobacter jejuni temperate bacteriophages has increasingly been associated with specific biological effects. It has recently been demonstrated that the presence of the prophage CJIE1 is associated with increased adherence and invasion of C. jejuni isolates in cell culture assays. RESULTS: Quantitative comparative proteomics experiments were undertaken using three closely related isolates with CJIE1 and one isolate without CJIE1 to determine whether there was a corresponding difference in protein expression levels. Initial experiments indicated that about 2% of the total proteins characterized were expressed at different levels in isolates with or without the prophage. Some of these proteins regulated by the presence of CJIE1 were associated with virulence or regulatory functions. Additional experiments were conducted using C. jejuni isolates with and without CJIE1 grown on four different media: Mueller Hinton (MH) media containing blood; MH media containing 0.1% sodium deoxycholate, which is thought to result in increased expression of virulence proteins; MH media containing 2.5% Oxgall; and MHwithout additives. These experiments provided further evidence that CJIE1 affected protein expression, including virulence-associated proteins. They also demonstrated a general bile response involving a majority of the proteome and clearly showed the induction of almost all proteins known to be involved with iron acquisition. The data have been deposited to the ProteomeXchange with identifiers PXD000798, PXD000799, PXD000800, and PXD000801. CONCLUSION: The presence of the CJIE1 prophage was associated with differences in protein expression levels under different conditions. Further work is required to determine what genes are involved in causing this phenomenon.

SUBMITTER: Clark CG

PROVIDER: S-EPMC4004267 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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The CJIE1 prophage of Campylobacter jejuni affects protein expression in growth media with and without bile salts.

Clark Clifford G CG Chong Patrick M PM McCorrister Stuart J SJ Simon Philippe P Walker Matthew M Lee David M DM Nguy Kimberly K Cheng Keding K Gilmour Matthew W MW Westmacott Garrett R GR

BMC microbiology 20140319

<h4>Background</h4>The presence of Campylobacter jejuni temperate bacteriophages has increasingly been associated with specific biological effects. It has recently been demonstrated that the presence of the prophage CJIE1 is associated with increased adherence and invasion of C. jejuni isolates in cell culture assays.<h4>Results</h4>Quantitative comparative proteomics experiments were undertaken using three closely related isolates with CJIE1 and one isolate without CJIE1 to determine whether th ...[more]

PMID: 24641125

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Project description:Campylobacter jejuni carry temperate bacteriophages that can affect the biology or virulence of the host bacterium. Known effects include genomic rearrangements and resistance to DNA transformation. C. jejuni prophage CJIE1 shows sequence variability and variability in the content of morons. Homologs of the CJIE1 prophage enhance both adherence and invasion to cells in culture and increase the expression of a specific subset of bacterial genes. Other C. jejuni temperate phages have so far not been well characterized. In this study we describe investigations into the DNA sequence variability and protein expression in a second prophage, CJIE4. CJIE4 sequences were obtained de novo from DNA sequencing of five C. jejuni isolates, as well as from whole genome sequences submitted to GenBank by other research groups. These CJIE4 DNA sequences were heterogenous, with several different insertions/deletions (indels) in different parts of the prophage genome. Two variants of a 3-4 kb region inserted within CJIE4 had different gene content that distinguished two major conserved CJIE4 prophage families. Additional indels were detected throughout the prophage. Detection of proteins in the five isolates characterized in our laboratory in isobaric Tags for Relative and Absolute Quantitation (iTRAQ) experiments indicated that prophage proteins within each of the two large indel variants were expressed during growth of the bacteria on Mueller Hinton agar plates. These proteins included the extracellular DNase associated with resistance to DNA transformation and prophage repressor proteins. Other proteins associated with known or suspected roles in prophage biology were also expressed from CJIE4, including capsid protein, the phage integrase, and MazF, a type II toxin-antitoxin system protein. Together with the results previously obtained for the CJIE1 prophage these results demonstrate that sequence variability and expression of moron genes are both general properties of temperate bacteriophages in C. jejuni.

Project description:Temperate bacteriophages (prophages) have recently been demonstrated in Campylobacter jejuni. However, what they do there is largely unknown. In the series of studies that are the subject of these submissions we have investigated the relative expression levels of proteins in C. jejuni isolates that differ in the presence or absence of the CJIE1 prophage. At the time of the initial investigations whole genome sequence data were not available for the isolates used, though DNA microarray data indicated that the isolates were very closely related. The overall project was carried out through four separate experiments. The first set of experiments (experiment 1) therefore compared protein expression in 4-plex iTRAQ experiments using three isolates carrying the (previously sequenced) prophage with a fourth isolate that was epidemiologically and genetically related to these isolates but which naturally lacked the CJIE1 prophage. Three replicate experiments were done. These isolates were grown on medium containing blood to obtain optimal growth and determine whether any differences were found. Three replicate experiments were done. However, since these growth conditions may not mimic in vivo growth of the organism the results may not be considered relevant or very interesting. Previous work in the scientific literature indicated that growth on medium lacking blood but containing sodium deoxycholate induced the expression of at least some proteins associated with virulence and provided data thought to be of relevance to the virulence of the bacterium. Therefore two isolates were chosen, one with and one without the CJIE1 prophage. Each of three replicates of a 4-plex iTRAQ experiment compared protein expression of the two isolates (00-2425 and 00-2426) after growth on Mueller-Hinton agar with and without 0.1% sodium deoxycholate. There was pretty good overlap between the proteins expressed in the first two experiments but, because all results were expressed as log2 change values, it was difficult to determine whether the expression of some proteins was completely absent in one or the other isolate. As well, protein expression overall showed quite extensive differences compared with the first experiment that we attributed to the lack of blood in the growth medium; we thought we might be seeing a response to limited iron as well. Finally, the response to the deoxycholate was extensive, and we wished to further explore this phenomenon as a means of determining or verifying what effects were due to the presence of the CJIE1 prophage and which were due to other differences. Further 4-plex iTRAQ experiments compared protein expression for each of isolate after growth on medium containing blood, without blood, without blood plus sodium deoxycholate, and without blood plus 2.5% Oxgall. Comparison of the results for isolate 00-2425 (with the CJIE1 prophage) and 00-2426 (without the prophage) identified a small number of proteins that could not be detected in one or the other isolate and allowed discrimination of the effects of the prophage from the responses to iron limitation and bile salt preparations. This dataset is associated with the first experiment, experiment 1, which compares C. jejuni isolates carrying the CJIE1 prophage (00-2425, 00-2538, 00-2544) with a very closely related isolate lacking the prophage (00-2426)

Dataset Information

The CJIE1 prophage of Campylobacter jejuni affects protein expression in growth media with and without bile salts.

Publications

The CJIE1 prophage of Campylobacter jejuni affects protein expression in growth media with and without bile salts.

Similar Datasets

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