Project description:Two component sensor-response regulator systems (TCSs) are very common in the genomes of the Streptomyces species that have been fully sequenced to date. It has been suggested that this large number is an evolutionary response to the variable environment that Streptomyces encounter in soil. Notwithstanding this, TCSs are also more common in the sequenced genomes of other Actinomycetales when these are compared to the genomes of most other eubacteria. In this study, we have used DNA/DNA genome microarray analysis to compare fourteen Streptomyces species and one closely related genus to Streptomyces coelicolor in order to identify a core group of such systems. This core group is compared to the syntenous and non-syntenous TCSs present in the genome sequences of other Actinomycetales in order to separate the systems into those present in Actinomycetales in general, the Streptomyces specific systems and the species specific systems. Horizontal transfer does not seem to play a very important role in the evolution of the TCS complement analyzed in this study. However, cognate pairs do not necessarily seem to evolve at the same pace, which may indicate the evolutionary responses to environmental variation may be reflected differently in sequence changes within the two components of the TCSs. The overall analysis allowed subclassification of the orphan TCSs and the TCS cognate pairs and identification of possible targets for further study using gene knockouts, gene overexpression, reporter genes and yeast two hybrid analysis.
Project description:In the seabed, chemical defences mediate inter- and intraspecific interactions and may determine organisms’ success, shaping the diversity and function of benthic communities. Sponges represent a prominent example of chemically-defended marine organisms with great ecological success. The ecological factors controlling the production of their defensive compounds and the evolutionary forces that select for these defences remain little understood. Each sponge species produces a specific and diverse chemical arsenal with fish-deterrent, antifouling and antimicrobial properties. However, some small animals (mesograzers), mainly sea slugs, have specialized in living and feeding on sponges. Feeding on chemically-defended organisms provides a strategy to avoid predators, albeit the poor nutritional value of sponges. In order to investigate the mechanisms that control sponge chemical defence, with particular focus on the response to specialist grazers, we investigated the interaction between the sponge Aplysina aerophoba and the sea slug Tylodina perversa. Here we performed controlled experiments and collected sponge samples at different time points (3h, 1d and 6d after treatment). To further elucidate if the sponge response is specific to grazing by T. perversa, we also included a treatment in which sponges were mechanically damaged with a scalpel. We compared gene expression between treatments based on RNA-Seq data.
Project description:A vast portion of the mammalian genome is transcribed as long non-coding RNAs (lncRNAs) acting in the cytoplasm with largely unknown functions. Surprisingly, lncRNAs have been shown to interact with ribosomes, encode uncharacterized proteins, or act as ribosome sponges. These functions still remain mostly undetected and understudied owing to the lack of efficient tools for genome-wide simultaneous identification of ribosome-associated lncRNAs and peptide-producing lncRNAs. Here we present AHARIBO, a method for the detection of lncRNAs either untranslated, but associated with ribosomes, or encoding small peptides. Using AHARIBO in mouse embryonic stem cells during neuronal differentiation, we isolated ribosome-protected RNA fragments, translated RNAs and corresponding de novo synthesized polypeptides. Besides identifying mRNAs under active translation and associated ribosomes, we found and distinguished lncRNAs acting as ribosome sponges or encoding micropeptides, laying the ground for a better functional understanding of hundreds lncRNAs.
Project description:The mass spec data for PRMPs detected in marine sponges is deposited. Also the data differentiating leucine and isoleucine residues in cyclic peptides is deposited.