Project description:Transposable elements (TEs) pose a threat to genome integrity, and the piRNA pathway in animal gonads plays a crucial role in silencing TE activity. While the transcriptional regulation of piRNA pathway components in germline cells is well understood, the mechanisms orchestrating the transcriptional program of the somatic piRNA pathway in surrounding somatic cells remains poorly defined. Here, we demonstrate that Traffic Jam (Tj), an orthologue of a large Maf transcription factor in mammals, is a master regulator of the somatic piRNA pathway playing a crucial role in maintaining TE silencing and genomic integrity in somatic tissues . We show that Tj directly binds to the promoters of piRNA factors such as fs(1)Yb, nxf2, panx, and armi, as well as the flamenco piRNA cluster, a major locus for TE silencing in somatic cells. Knockdown of Tj in somatic follicle cells results in significant downregulation of these piRNA factors, a complete loss of flam expression, and derepression of TEs. We have identified an enhancer downstream of the flam promoter, including TJ binding sites, essential for high and specific flam expression in ovarian follicle cells in adult ovaries. This work uncovers a previously unappreciated layer of transcriptional regulation oc the piRNA pathway and we propose that Tj evolved to orchestrate the somatic piRNA pathway expression, ensuring efficient TE silencing in somatic cells that support germ cells, thereby preventing instability from being transmitted to the offspring.
Project description:This study uses iTRAQ based proteomics approach to understand the cellular metabolic machineries present within the Clostridium strain BOH3 (discovered by our group) which can simultaneously utilise both glucose (six carbon sugar) and xylose (five carbon sugar) to produce butanol and riboflavin.
Project description:Transposable elements (TEs) pose a threat to genome integrity, and the piRNA pathway in animal gonads plays a crucial role in silencing TE activity. While the transcriptional regulation of piRNA pathway components in germline cells is well understood, the mechanisms orchestrating the transcriptional program of the somatic piRNA pathway in surrounding somatic cells remains poorly defined. Here, we demonstrate that Traffic Jam (Tj), an orthologue of a large Maf transcription factor in mammals, is a master regulator of the somatic piRNA pathway playing a crucial role in maintaining TE silencing and genomic integrity in somatic tissues . We show that Tj directly binds to the promoters of piRNA factors such as fs(1)Yb, nxf2, panx, and armi, as well as the flamenco piRNA cluster, a major locus for TE silencing in somatic cells. Knockdown of Tj in somatic follicle cells results in significant downregulation of these piRNA factors, a complete loss of flam expression, and derepression of TEs. We have identified an enhancer downstream of the flam promoter, including TJ binding sites, essential for high and specific flam expression in ovarian follicle cells in adult ovaries. This work uncovers a previously unappreciated layer of transcriptional regulation oc the piRNA pathway and we propose that Tj evolved to orchestrate the somatic piRNA pathway expression, ensuring efficient TE silencing in somatic cells that support germ cells, thereby preventing instability from being transmitted to the offspring.
Project description:Clostridium difficile is a gram-positive, spore-forming enteric anaerobe which can infect humans and a wide variety of animal species. Recently, the incidence and severity of human C. difficile infection has markedly increased. In this study, we evaluated the genomic content of 73 C. difficile strains isolated from humans, horses, cattle, and pigs by comparative genomic hybridization with microarrays containing coding sequences from C. difficile strains 630 and QCD-32g58. The sequenced genome of C. difficile strain 630 was used as a reference to define a candidate core genome of C. difficile and to explore correlations between host origins and genetic diversity. Approximately 16% of the genes in strain 630 were highly conserved among all strains, representing the core complement of functional genes defining C. difficile. Absent or divergent genes in the tested strains were distributed across the entire C. difficile 630 genome and across all the predicted functional categories. Interestingly, certain genes were conserved among strains from a specific host species, but divergent in isolates with other host origins. This information provides insight into the genomic changes which might contribute to host adaptation. Due to a high degree of divergence among C. difficile strains, a core gene list from this study offers the first step toward the construction of diagnostic arrays for C. difficile.investigated by determining changes in transcript profiles when aerobic steady-state cultures were depleted of air.
Project description:Clostridium difficile is a gram-positive, spore-forming enteric anaerobe which can infect humans and a wide variety of animal species. Recently, the incidence and severity of human C. difficile infection has markedly increased. In this study, we evaluated the genomic content of 73 C. difficile strains isolated from humans, horses, cattle, and pigs by comparative genomic hybridization with microarrays containing coding sequences from C. difficile strains 630 and QCD-32g58. The sequenced genome of C. difficile strain 630 was used as a reference to define a candidate core genome of C. difficile and to explore correlations between host origins and genetic diversity. Approximately 16% of the genes in strain 630 were highly conserved among all strains, representing the core complement of functional genes defining C. difficile. Absent or divergent genes in the tested strains were distributed across the entire C. difficile 630 genome and across all the predicted functional categories. Interestingly, certain genes were conserved among strains from a specific host species, but divergent in isolates with other host origins. This information provides insight into the genomic changes which might contribute to host adaptation. Due to a high degree of divergence among C. difficile strains, a core gene list from this study offers the first step toward the construction of diagnostic arrays for C. difficile.
Project description:Grad-seq in Clostridium difficile 630. Cell lysate is analyzed in a gradient and fractionated into 21 fractions which are analysed for proteins by MS and for transcripts by RNA-sequencing.