Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.
Project description:Histone H1 variants, known as linker histones, are essential chromatin components in higher eukaryotes, yet compared to the core histones relatively little is known about their in vivo functions. The filamentous fungus Neurospora crassa encodes a single H1 protein that is not essential for viability. To investigate the role of N. crassa H1, we constructed a functional FLAG-tagged H1 fusion protein and performed genomic and molecular analyses. Cell fractionation experiments showed that H1-FLAG is a chromatin binding protein. Chromatin-immunoprecipitation combined with sequencing (ChIP-seq) revealed that H1-3XFLAG is globally enriched throughout the genome with a subtle preference for promoters of expressed genes. In mammals, the stochiometery of H1 impacts nucleosome repeat length. To determine if H1 impacts nucleosome occupancy or nucleosome positioning in N. crassa, we performed micrococcal nuclease digestion in wildtype and the ∆hH1 strain followed by sequencing (MNase-Seq). Deletion of hH1 did not significantly impact nucleosome positioning or nucleosome occupancy. Analysis of DNA methylation using methylC-sequencing (mC-Seq) revealed a modest but global increase in DNA methylation in the ∆hH1 mutant. Together, these data suggest that H1 acts as a non-specific chromatin binding protein that can limit accessibility of the DNA methylation machinery in N. crassa.
Project description:CDT-1 and CDT-2 are two cellodextrin transporters discovered in the filamentous fungus Neurospora crassa. Previous studies focused on characterizing the role of these transporters in only a few conditions, including cellulose degradation, and the function of these two transporters is not yet completely understood. In this study, we show that deletion of cdt-2, but not cdt-1, results in growth defects not only on Avicel but also on xylan. cdt-2 can be highly induced by xylan, and this mutant has a xylodextrin consumption defect. Transcriptomic analysis of the cdt-2 deletion strain on Avicel and xylan showed that major cellulase and hemicellulase genes were significantly down-regulated in the cdt-2 deletion strain and artificial over expression of cdt-2 in N. crassa increased cellulase and hemicellulase production. Together, these data clearly show that CDT-2 plays a critical role in hemicellulose sensing and utilization. This is the first time a sugar transporter has been assigned a function in the hemicellulose degradation pathway. Furthermore, we found that the transcription factor XLR-1 is the major regulator of cdt-2, while cdt-1 is primarily regulated by CLR-1. These results deepen our understanding of the functions of both cellodextrin transporters, particularly for CDT-2. Our study also provides novel insight into the mechanisms for hemicellulose sensing and utilization in N. crassa, and may be applicable to other cellulolytic filamentous fungi. N. crassa was pregrown in Sucrose and transferred to Avicel (cellulose) or Xylan(hemicellulose) media. Up regulated and down regulated genes expressions were compared with wild type strain on two conditions (Avicel and xylan) respectively.
Project description:NO-CUT is a one-stage phase II trial seeking to establish whether an oxaliplatin-based chemotherapy preceding standard neo-adjuvant fluoropyrimidines-based chemo radiotherapy, can safely spare demolitive surgical intervention in patients with operable rectal cancer, without increasing the risk of distant relapse. The trial also has a translational component aimed at establishing whether selected genomic, epigenetic, and transcriptomic markers are predictive of tumor and patient outcome.
Project description:The purpose of this study is the investigation of new host-microbiome interactions promoting adenoma formation and adenocarcinoma progression. For that purpose, the investigators will collect saliva, stool and colon biopsy specimens from patients referred to colonoscopy or surgical resection of colorectal tumor. Besides, a questionnaire about diet, lifestyle and medical history will be collected. Sample analysis will involve simultaneous characterization of host and microbiota genomic and transcriptomic components.