RNA-Seq of Cellulophaga baltica and its phage phi14:2 during the infection process
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ABSTRACT: We performed high-througput RNA sequencing of RNA samples extracted from C. baltica cells infected with phi14:2 phage at 40, 90, 140 and 190 minutes after infection. The same experiments were performed with cells treated with host RNA polymerase inhibitor in order to determine which genes rely on viral rifampicin-insensitive RNA polymerase. Using this data, we identified different time classes of phage genes and revealed genes transcribed by phage RNA polymerase.
Project description:Genome-wide transcriptomics (RNA-seq) data was obtained temporally at 0, 15, 30, 45, 60 and 120 minutes of the infection with phage 18:3 on Cellulophaga baltica strain #18 to analyze, in biological triplicates, the phage and host transcriptional response during their interaction compared to the uninfected control.
Project description:To better understand host/phage interactions and the genetic bases of phage resistance in a model system relevant to potential phage therapy, we isolated several spontaneous mutants of the USA300 S. aureus clinical isolate NRS384 that were resistant to phage K. Six of these had a single missense mutation in the host rpoC gene, which encodes the RNA polymerase beta prime subunit. To examine the hypothesis that the mutations in the host RNA polymerase affect the transcription of phage genes, we performed RNA-seq analysis on total RNA samples collected from NRS384 wild-type (WT) and rpoC G17D mutant cultures infected with phage K, at different time points after infection. Infection of the WT host led to a steady increase of phage transcription relative to the host. Our analysis allowed us to define different early, middle, and late phage genes based on their temporal expression patterns and group them into transcriptional units. Predicted promoter sequences defined by conserved -35, -10, and in some cases extended -10 elements were found upstream of early and middle genes. However, sequences upstream of late genes did not contain clear, complete, canonical promoter sequences, suggesting that factors in addition to host RNA polymerase are required for their regulated expression. Infection of the rpoC G17D mutant host led to a transcriptional pattern that was similar to the WT at early time points. However, beginning at 20 minutes after infection, transcription of late genes (such as phage structural genes and host lysis genes) was severely reduced. Our data indicate that the rpoCG17D mutation prevents the expression of phage late genes, resulting in a failed infection cycle for phage K. In addition to illuminating the global transcriptional landscape of phage K throughout the infection cycle, these studies can inform our investigations into the bases of phage K’s control of its transcriptional program as well as mechanisms of phage resistance.
Project description:Dinoroseobacter shibae DFL12T was cultured with/without phage R2C, and gene expression was analyzed at 60 min and 140 min during the incubation
Project description:Expression profiling of the stress response of the marine Planctomycete Rhodopirellula baltica after a temperature up-shift. R. baltica cultures were grown at 28°C and then shifted to 6°C. Samples were taken after 10, 20, 40, 60 and 300min and compared with cultures before the up-shift (28°C).
Project description:Expression profiling of the stress response of the marine Planctomycete Rhodopirellula baltica after a salinity up-shift. R. baltica cultures were grown at 28°C in mineral media with 17.5% salinity and up-shifted to 59.9%. Samples were taken after 10, 20, 40, 60 and 300min and compared with cultures before the up-shift.
Project description:Expression profiling of the stress response of the marine Planctomycete Rhodopirellula baltica after a temperature up-shift. R. baltica cultures were grown at 28°C and then shifted to 37°C. Samples were taken after 10, 20, 40, 60 and 300min and compared with cultures before the up-shift (28°C). Time series experiment, whole genome array
Project description:Pseudomonas aeruginosa bacteriophage PhiKZ is the type representative of the M-bM-^@M-^XgiantM-bM-^@M-^Y phage genus with unusually large virions and genomes. By unraveling the transcriptional map of the 280 kb genome to single-nucleotide resolution, we show that it encodes 369 genes organized in 134 operons, 20% more than originally annotated. Early transcription is initiated from 28 highly conserved AT-rich promoters distributed over the PhiKZ genome, all located on the same strand. Transcription of middle and late genes is dependent on protein synthesis and mediated by very poorly conserved middle (6) and late (16) promoters. As a result of massive PhiKZ transcription, halfway through infection only 1.5% of all mRNAs in the infected cell remain bacterial. Unique to PhiKZ is its ability to complete its infection in complete absence of bacterial RNA polymerase (RNAP) enzyme activity. Its transcription is performed by the consecutive action of two PhiKZ-encoded, non-canonical RNAPs, one of which is packed within the virion. This unique, rifampicin-resistant transcriptional machinery is conserved among giant viruses, seems to function without auxiliary factors and might have its origin preceding the split between Gram-positive and Gram-negative bacteria. Construction of transcription maps for the PhiKZ phage and analysis of differential expression of host and phage genes using RNA-Seq data from samples taken in duplicate at 0, 5, 10, 15, and 35 minutes into infection.
Project description:Viral genomes are most vulnerable to cellular defenses at the start of the infection. A family of jumbo phages related to phage ΦKZ, which infects Pseudomonas aeruginosa, assembles a protein-based phage nucleus to protect replicating phage DNA, but how it is protected prior to phage nucleus assembly is unclear. We find that host proteins related to membrane and lipid biology interact with injected phage protein, clustering in an early phage infection (EPI) vesicle. The injected virion RNA polymerase (vRNAP) executes early gene expression until phage genome separation from the vRNAP and the EPI vesicle, moving into the nascent proteinaceous phage nucleus. Enzymes involved in DNA replication and CRISPR/restriction immune nucleases are excluded by the EPI vesicle. We propose that the EPI vesicle is rapidly constructed with injected phage proteins, phage DNA, host lipids, and host membrane proteins to enable genome protection, early transcription, localized translation, and to ensure faithful genome transfer to the proteinaceous nucleus.