Project description:To further characterize the organization of the transcriptional units and the global behaviour of the genomic island ICEclc in Pseudomonas knackmussii, we have employed Agilent DNA custom microarray in the 8X15K format.
Project description:To support our molecular hypothesis of the effect of rpoS and inrR genes over the activation of the ICEclc genome in Pseudomonas knackmussii B13, we have employed Agilent DNA custom microarray in the 8X15K format. ICEclc-specific gene expression in Pseudomonas knackmussii strain B13 was measured after 48 hours of stationary phase following a growth on 10mM 3-chlorobenzoate (3CBA) as sole carbon and energy source. Various genotypes were tested: wild type (strain nM-BM-078, in 5 replicates), inrR-/- (strain 2201, in triplicates), delta::rpoS (strain 2671, in triplicates).
Project description:To support our molecular hypothesis of the effect of rpoS and inrR genes over the activation of the ICEclc genome in Pseudomonas knackmussii B13, we have employed Agilent DNA custom microarray in the 8X15K format.
Project description:BackgroundIntegrative and conjugative elements (ICE) form a diverse group of DNA elements that are integrated in the chromosome of the bacterial host, but can occasionally excise and horizontally transfer to a new host cell. ICE come in different families, typically with a conserved core for functions controlling the element's behavior and a variable region providing auxiliary functions to the host. The ICEclc element of Pseudomonas knackmussii strain B13 is representative for a large family of chromosomal islands detected by genome sequencing approaches. It provides the host with the capacity to degrade chloroaromatics and 2-aminophenol.ResultsHere we study the transcriptional organization of the ICEclc core region. By northern hybridizations, reverse-transcriptase polymerase chain reaction (RT-PCR) and Rapid Amplification of cDNA Ends (5'-RACE) fifteen transcripts were mapped in the core region. The occurrence and location of those transcripts were further confirmed by hybridizing labeled cDNA to a semi-tiling micro-array probing both strands of the ICEclc core region. Dot blot and semi-tiling array hybridizations demonstrated most of the core transcripts to be upregulated during stationary phase on 3-chlorobenzoate, but not on succinate or glucose.ConclusionsThe transcription analysis of the ICEclc core region provides detailed insights in the mode of regulatory organization and will help to further understand the complex mode of behavior of this class of mobile elements. We conclude that ICEclc core transcription is concerted at a global level, more reminiscent of a phage program than of plasmid conjugation.
