Project description:microRNAs (miRNAs) are small non-coding RNA-molecules that influence translation by binding to the target gene mRNA. Many miRNAs are found in nested arrangements within introns, or exons, of larger protein-coding host genes. miRNAs and host genes in a nested arrangement are often transcribed simultaneously, which may indicate that both have similar functions. miRNAs have been implicated in regulating defense responses against pathogen infection in C. elegans and in mammals. Here, we asked if miRNAs in nested arrangements and their host genes are involved in the C. elegans response against infection with Bacillus thuringiensis (Bt). We performed miRNA sequencing and functional genetic analysis of miRNA and/or host gene in four nested arrangements. We identified mir-58.1 and mir-2 as negative regulators of C. elegans resistance to Bt infection. However, we did not find any miRNA/host gene pair in which both contribute to defense against Bt.
Project description:Transcriptional profiling of C. elegans nasp-1 / btr-1 mutant worms versus wild type N2 strain, both exposed to the bacterial pathogen Bacillus thuringiensis DB27. One-condition experiment. C. elegans nasp-1 / btr-1 mutant versus N2, exposed to Bacillus thuringiensis DB27. 3 biological replicates, including 1 dye-swaps.
Project description:Transcriptional profiling of C. elegans nasp-1 / btr-1 mutant worms versus wild type N2 strain, both exposed to the bacterial pathogen Bacillus thuringiensis DB27.
Project description:In the past decade, the paradigm which claimed that invertebrate immune systems lack specificity has been reconsidered. Accumulating evidence supports that invertebrate immune systems are able to mount specific responses to the pathogen species-, and even to the pathogen strain-level. However, the underlying molecular mechanisms behind invertebrate immune specificity remain mostly unknown. Studying the molecular basis of invertebrate immune specificity in a genetically tractable model, such as the nematode Caenorhabditis elegans, has the potential to reveal insights into the immune systems of other metazoans, including humans. We chose to study the mechanisms of specific immune responses of the worm to two different pathogenic strains of the Gram-positive bacterium Bacillus thuringiensis (MYBY18247 and MYBT18679), because there is phenotypic evidence of specific genotype-genotype interactions between this host-pathogen pair. We did an initial RNA-Seq experiment upon pathogen exposure and found that 9% of the differentially expressed genes change their expression in different ways when comparing the two pathogen strains. Through promoter region motif enrichment analysis, we found the GATA transcription factor ELT-2 is responsible for the pathogen strain-specific transcriptomic response. Upon elt-2 knockdown worms exposed to MYBT18679 display lower survival rate coupled with higher intestinal damage than non-infected controls. Additionally, by performing further genetic analysis using gene knockdown and knockout, we found that the p38 MAPK pathway acts likely in parallel to elt-2 and the transcription factor skn-1 cooperates with elt-2 to promote resistance to MYBT18679. On the other hand, elt-2 knockdown leads to a substantially higher survival rate, together with lower intestinal tissue damage compared to control worms, upon exposure to MYBT18247, another pathogenic Bacillus thuringiensis strain. The MYBT18247 pathogen load of elt-2(RNAi) worms compared to control worms remained unchanged, suggesting the elt-2 negatively regulates tolerance towards MYBT18247. We found that tolerance to MYBT18247 was positively regulated by the transcription factors: FOXO daf-16, bZip zip-2, nhr-99 and nhr-193. To identify elt-2 negatively-regulated downstream targets that could promote tolerance to MYBT18247, we performed a second RNA-Seq experiment, this time including elt-2(RNAi) worms exposed to both pathogenic strains. We found four genes negatively regulated by elt-2: cdr-2, poml-3, dhs-30 and tre-3, with putative function in detoxification and lipid metabolism, which can mediate tolerance to MYBT18247. We conclude that ELT-2 coordinates strain-specific immune responses in this invertebrate host and promotes resistance upon exposure to MYBT18679, while it negatively regulates tolerance to MYBT18247. The response is likely to be specific to the crystal pore-forming toxins produced by this pathogen.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Bacillus thuringiensis DB27 for 4 hours versus age-matched worms exposed to onctrol lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Staphylococcus aureus, Serratia marcescens, Xenorhabdus nematophila. Keywords: Expression profiling by array One-condition experiments. C. elegans young adults: Exposed to Bacillus thuringiensis DB27 versus exposed to E. coli OP50 : 4 hours. 3 biological replicates for each condition, including 1 dye-swap.
Project description:Transcriptional profiling of C. elegans young adult worms exposed to pathogen Bacillus thuringiensis DB27 for 4 hours versus age-matched worms exposed to onctrol lab food E. coli OP50. The goal was to identify genes regulated in response to pathogen. The broader goal of study was to study evolution of pathogen response by comparing this expression profile to that obtained by exposing the nematode Pristionchus pacificus to the same pathogen. Other experiments which are a part of this study include expression profiling of C. elegans and P. pacificus on other pathogens including Staphylococcus aureus, Serratia marcescens, Xenorhabdus nematophila. Keywords: Expression profiling by array
Project description:The C. elegans lifespan in the presence of Bacillus licheniformis caused induction of a large number of genes associated with anti-aging activiy including beta-oxidation Inaddition, these results indicate the B. licheniformis enhances the lifespan of Caenorhabditis elegans through serotonin signaling