Project description:Members of the third domain of life, the Archaea, are ubiquitous in all environments on Earth but remain understudied in many aspects including regulatory processes of the central dogma. Archaea present unique biology because they utilize a mosaic of molecular features from both Bacteria and Eukarya, along with unique features. The advent of a high-throughput view of the translation landscape via ribosome profiling in the Bacteria and the Eukarya has illuminated the complexity and previously underappreciated regulation of translation (i.e. translation efficiency, ribosome surveillance, etc.) that potentially has large scale effects on cellular functionality. Here, we developed ribosome profiling in a model archaeon, Haloferax volcanii and elucidated the translational landscape for the first time in the third domain of life. We coupled ribosome profiling with translation inhibitors to: (a) determine the size of the archaeal ribosome footprint, (b) systematically assign translation states of the ribosome to footprint lengths in a mostly leaderless transcriptome, (c) experimentally induce ribosome pauses and clarify the pausing landscape comprehensively, (d) identify putative novel proteins, including small open reading frames (smORFs), and (e) provide evidence that many genes initiate on putative alternative translation start sites (paTSS) around and within open reading frames (ORFs), demonstrating how a microorganism with a gene dense genome can produce proteins with distinct functions using the same gene.
Project description:Small RNAs have been studied in detail in Bacteria and Eukarya domain, but in the case of Archaea domain the knowledge is scarce and the physiological function of the majority is still uncertain. To extend the knowledge of sRNAs in Archaea domain and its possible role in the regulation of the nitrogen assimilation metabolism in haloarchaea, Haloferax mediterranei has been used as a model microorganism. Bioinformatic approach has allowed to predict 295 putative sRNAs genes in the genome of H. mediterranei, 88 of which have been verified by means of RNA-seq. The secondary structure of putative sRNAs and its possible targets have been identified. Curiously, some of them present as possible targets genes related to the nitrogen assimilation, as glutamate dehydrogenase or regulatory nitrogen protein PII. Analysis of RNA-seq data has also revealed differences in the expression pattern of 16 sRNAs according to the nitrogen source. Consequently, RNomic and the bioinformatic approaches used in this work have allowed the identification of new sRNAs in Hfx. mediterranei, some of which show different expression pattern depending on the nitrogen source. It suggests that these sRNAs could be involved in the regulation of nitrogen assimilation, being able to constitute important gene regulatory network.
Project description:The airway epithelium represents a critical component of the human lung that helps orchestrate defences against respiratory tract viral infections, which are responsible for more than 2.5 million deaths/year globally. Innate immune activities of the airway epithelium rely Toll-like receptors (TLRs), nucleotide binding and leucine-rich-repeat pyrin domain containing (NLRP) receptors, and cytosolic nucleic acid sensors. ATP Binding Cassette (ABC) transporters are ubiquitous across all three domains of life – Archaea, Bacteria, and Eukarya – and expressed in the human airway epithelium. ABCF1, a unique ABC family member that lacks a transmembrane domain, has been defined as a cytosolic nucleic acid sensor that regulates CXCL10, interferon-b expression, and downstream type I interferon responses. We tested the hypothesis that ABCF1 functions as a dsDNA nucleic acid sensor in human airway epithelial cells important in regulating antiviral responses.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals.
Project description:The increased urban pressures are often associated with specialization of microbial communities. Microbial communities being a critical player in the geochemical processes, makes it important to identify key environmental parameters that influence the community structure and its function.In this proect we study the influence of land use type and environmental parameters on the structure and function of microbial communities. The present study was conducted in an urban catchment, where the metal and pollutants levels are under allowable limits. The overall goal of this study is to understand the role of engineered physicochemical environment on the structure and function of microbial communities in urban storm-water canals. Microbial community structure was determined using PhyoChio (G3)
Project description:Cornelia de Lange syndrome (CdLS) is a complex multisystem developmental disorder caused by mutations in cohesin subunits and regulators. While the precise molecular mechanisms are not well defined, they point toward a global deregulation of the transcriptional gene expression program. Indeed, cohesin is associated with the boundaries of chromosome domains in addition to enhancers and promoters connecting the 3D genome organization with transcriptional control and gene expression. Here we show that connected gene communities, built with noncoding regulatory elements and genes physically interacting in the 3D chromosomal space, provide a molecular explanation for the pathoetiology of CdLS. Indeed, NIPBL and cohesin are important constituents of connected gene communities, both being centrally positioned at active noncoding regulatory elements. Interestingly, mutations in SMC1A and NIPBL lead to coordinated gene expression changes in connected communities. Our findings suggest a model where CdLS is explained by coordinated modulation of connected gene communities.
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).