Project description:The remarkable survival of the hyperthermophilic archaeon Pyrococcus furiosus to ionizing radiation was previously demonstrated. Using a time course study and whole-genome microarray analyses of mRNA transcript levels, the genes and regulatory pathways involved in the repair of lesions produced by ionizing irradiation (oxidative damage and DNA strand breaks) in P. furiosus were investigated. Data analyses showed that radA, encoding the archaeal homolog of the RecA/Rad51 recombinase, was moderately up regulated by irradiation and that a putative DNA-repair gene cluster was specifically induced by exposure to ionizing radiation. This novel repair system appears to be unique to thermophilic archaea and bacteria and is suspected to be involved in translesion synthesis. Genes that encode for a putative Dps-like iron-chelating protein and two membrane-bound oxidoreductases were differentially expressed following gamma irradiation, potentially in response to oxidative stress. Surprisingly, the many systems involved in oxygen detoxification and redox homeostasis appeared to be constitutively expressed. Finally, we identified several transcriptional regulators and protein kinases highly regulated in response to gamma irradiation. Keywords: time course
Project description:Organisms of the third domain of life, the Archaea, share molecular characteristics both with bacteria and eukarya. These organisms attract scientific attention as research models for regulation and evolution of processes such as transcription, translation and RNA processing. We have reconstructed the primary transcriptome of Sulfolobus solfataricus P2, one of the most widely studied model archaeal organisms. Analysis of 625 million bases of sequenced cDNAs yielded a single-bp resolution map of transcription start sites and operon structures for more than 1000 transcriptional units. The analysis led to the discovery of 310 expressed non-coding RNAs, with an extensive expression of overlapping cis-antisense transcripts to a level unprecedented in any bacteria or archaea but resembling that of eukaryotes. As opposed to bacterial transcripts, most Sulfolobus transcripts completely lack 5' UTR sequences, suggesting that mRNA/ncRNA interactions differ between bacteria and archaea. The data also reveal internal hotspots for transcript cleavage linked to RNA degradation, and predict sequence motifs that promote RNA destabilization. This study emphasizes the importance of transcriptome sequencing as a key tool for understanding the mechanisms and extent of RNA-based regulation for bacteria and archaea. 5 samples of cDNA sequencing (2 of these are replicates), and 3 samples of RACE-cDNA sequencing (described in the samples section).
Project description:We used one of the RNA-DNA proximity ligation approaches, RedC, for the analysis of an RNA-DNA interactome of microbial cells. We assess the distribution of main RNA types — mRNA, tRNA and rRNA — along the genomes of E.coli, B.subtilis, and thermophilic archaea T. adornatum.
Project description:Archaeal viruses display unusually high genetic and morphologic diversity. The Sulfolobus islandicus Rod Shaped Virus 2 (SIRV2) is a model to study virus-host interactions in Archaea. It is a lytic virus that exploits a unique egress mechanism based on formation of remarkable pyramidal structures on the host cell envelope. The hyperthermophilic Sulfolobus islandicus LAL14/1 is the natural host for SIRV2. RNA was isolated at 0,1,2,3,5,7 and 9 hours after SIRV2 infection of two S.islandicus cultures and analysed with whole transcriptome sequencing (RNAseq). As a control RNA was isolated at the same time points from two uninfected cultures.