Project description:We identified target genes for NHR-25 by ChIP-seq at L1 stage of C. elegans. Transcription factor genes were tagged with GFP and their expression examined at L1 stage. Since there are no direct target genes known for NHR-25 that can be used for assessment of enrichment efficiency by quantitative PCR (qPCR), we chose to repeat ChIP-seq experiment of another GFP tagged transcription factor, PHA-4 for which the ChIP-seq was performed during a pilot experiment of modENCODE project using the same transgenic strain and antibody (a gift from Tony Hyman lab). pha-4 and nhr-25 transgenic worm were studied in Fed L1 stage.
Project description:We identified target genes for NHR-25 by ChIP-seq at L1 stage of C. elegans. Transcription factor genes were tagged with GFP and their expression examined at L1 stage. Since there are no direct target genes known for NHR-25 that can be used for assessment of enrichment efficiency by quantitative PCR (qPCR), we chose to repeat ChIP-seq experiment of another GFP tagged transcription factor, PHA-4 for which the ChIP-seq was performed during a pilot experiment of modENCODE project using the same transgenic strain and antibody (a gift from Tony Hyman lab).
Project description:The gene nhr-6 encodes the sole C. elegans NR4A nuclear receptor homolog which has a critical role in organogenesis by regulating the development of the spermatheca organ. Here we utilized chromatin immunoprecipitation followed by next-generation sequencing (ChIP-seq) to identify NHR-6 binding sites during both the late L3/early L4 and mid L4 developmental stages. Our results revealed 30,745 enriched binding sites for NHR-6 with sites specific to each developmental stage and sites found in both stages. Additionally, ~70% of enriched sites were found within 3 kb upstream of a gene transcription start site. Binding sites for a cohort of candidate target genes with probable functions in spermatheca organogenesis were validated through qPCR. Reproductive and spermatheca phenotypes were also evaluated for these genes following a loss-of-function RNAi screen which revealed several genes with critical functions during spermatheca organogenesis. Our results uncovered a complex nuclear receptor regulatory network whereby NHR-6 regulates multiple cellular processes including proliferation, differentiation, and metabolism.
Project description:The response to insufficient oxygen, termed hypoxia, is orchestrated by the conserved master regulator Hypoxia-Inducible Factor-1 (HIF-1), which is hyperactive in many cancers. Here, we describe a HIF-1 independent hypoxia response pathway controlled by Caenorhabditis elegans Nuclear Hormone Receptor NHR-49, an orthologue of mammalian lipid metabolism regulator Peroxisome Proliferator-Activated Receptor alpha (PPARα). nhr-49 is required for worm survival in hypoxia and is synthetically lethal with hif-1 in this context, demonstrating independent activity. RNA-seq data show that nhr-49 regulates a set of hif-1 independent hypoxia responsive genes, including autophagy genes that promote hypoxia survival. We further identified the Nuclear Hormone Receptor nhr-67 as a negative regulator and the Homeodomain-interacting Protein Kinase hpk-1 as a positive regulator in the NHR-49 pathway. Together, our experiments describe an essential hypoxia response pathway controlled by nhr-49 that includes new upstream and downstream components and is as important as hif-1 dependent hypoxia adaptation.
