Project description:To adapt SLAM-ITseq for Caenorhabditis elegans, we inserted a codon-optimized version of the Toxoplasma gondii UPRT gene downstream of a FRT-flanked mCh::his-58 cassette and under control of the strong and ubiquitous eft-3 promoter. We introduced a single copy of this construct into the C. elegans genome and crossed the resulting line with a dpy-7p::FLP driver. FLP-dependent expression of UPRT was confirmed by Western blotting (strain BN1190). As a proof of concept, we exposed animals to 4-TU from L3 to L4 stage and purified total RNA. RNA from animals without FLP expression was used to control for UPRT-independent labeling strain BN1158). RNA was alkylated with iodoacetamide, which leads to a T>C conversion of 4-TU-labeled positions during cDNA synthesis, and subjected to deep sequencing (see Materials and Methods). We confirmed that the presence of FLP and UPRT did not affect gene expression. Comparing the T>C conversion rate per gene revealed a significant increase in nematodes expressing UPRT in the hypodermis. Next, we performed a beta-binominal test to identify genes that were significantly labelled across all replicas, which retrieved 197 genes (p<0.003; FDR<0.1 after adjustment for multiple comparisons). Original SLAM-ITseq reference: Matsushima W, Herzog VA, Neumann T, Gapp K, Zuber J, Ameres SL, Miska EA (2018) SLAM-ITseq: sequencing cell type-specific transcriptomes without cell sorting. Development 145 (13). doi:10.1242/dev.164640
Project description:To adapt RNA polymerase DamID (RAPID) for FLP-mediated spatial control in Caenorhabditis elegans, we inserted a Dam::rpb-6 fusion gene downstream of a FRT-flanked mCh::his-58 cassette and under control of the hsp-16.41 promoter. We introduced a single copy of this construct into the C. elegans genome and crossed the resulting line with a dpy-7p::FLP driver to enable basal Dam::rpb-6 expression in the hypodermis. Nematodes were cultured at 20 degrees Celcius to ensure low levels of Dam::RPB-6 expression in the hypodermis and total genomic DNA was purified from L4 larvae. DNA from animals expressing GFP::Dam was used to control for unspecific methylation. The genome-wide association profile of Dam::RPB-6 was determined by deep sequencing, which revealed a list of 2331 protein coding genes with FDR < 0.05. Original RAPID reference: Gomez-Saldivar et al (2020) Tissue-Specific Transcription Footprinting Using RNA PoI DamID (RAPID) in Caenorhabditis elegans. Genetics 216, 931–945. doi:10.1534/genetics.120.303774
Project description:To identify genes differentially expressed during the molt, we collected RNA 30-40 minutes after feeding cessation at the start of the fourth larval stage (L4) lethargus. Additional time points for RNA collection were in the mid-L4 stage, approximately four hours prior to lethargus, and in the young adult stage, four hours after lethargus. These samples were interrogated with the Affymetrix C. elegans Genome Array. A total of 1,804 gene transcripts were up regulated, and 1,088 gene transcripts were down regulated, during the L4 lethargus period compared to the L4 and Adult stages (false discovery rate (FDR) < 0.05).
Project description:The roundworm Caenorhabditis elegans is a heme auxotroph that requires the coordinated actions of HRG-1 heme permeases to transport environmental heme into the intestine and HRG-3, a secreted protein, to deliver intestinal heme to other tissues including the embryo. Here we show that heme homeostasis in the extraintestinal hypodermal tissue is facilitated by the transmembrane protein HRG-2. Systemic heme deficiency upregulates hrg-2 mRNA expression over 200-fold in the main body hypodermal syncytium hyp 7. HRG-2 is a type I membrane protein which binds heme and localizes to the endoplasmic reticulum and apical plasma membrane. Cytochrome heme profiles are aberrant in HRG-2 deficient worms, a phenotype that is partially suppressed by heme supplementation. Heme-deficient yeast strain, ectopically expressing worm HRG-2, reveal significantly improved growth at submicromolar concentrations of exogenous heme. Taken together, our results implicate HRG-2 as a facilitator of heme utilization in the C. elegans hypodermis and provide a mechanism for regulation of heme homeostasis in an extraintestinal tissue. Two experimental groups: Group 1: three 4um Controls vs. three 4uM hrg-2 Mutants; Group 2: three 20um Controls vs. three 20uM hrg-2 Mutants
Project description:The roundworm Caenorhabditis elegans is a heme auxotroph that requires the coordinated actions of HRG-1 heme permeases to transport environmental heme into the intestine and HRG-3, a secreted protein, to deliver intestinal heme to other tissues including the embryo. Here we show that heme homeostasis in the extraintestinal hypodermal tissue is facilitated by the transmembrane protein HRG-2. Systemic heme deficiency upregulates hrg-2 mRNA expression over 200-fold in the main body hypodermal syncytium hyp 7. HRG-2 is a type I membrane protein which binds heme and localizes to the endoplasmic reticulum and apical plasma membrane. Cytochrome heme profiles are aberrant in HRG-2 deficient worms, a phenotype that is partially suppressed by heme supplementation. Heme-deficient yeast strain, ectopically expressing worm HRG-2, reveal significantly improved growth at submicromolar concentrations of exogenous heme. Taken together, our results implicate HRG-2 as a facilitator of heme utilization in the C. elegans hypodermis and provide a mechanism for regulation of heme homeostasis in an extraintestinal tissue.
Project description:To identify genes differentially expressed during the molt, we collected RNA 30-40 minutes after feeding cessation at the start of the fourth larval stage (L4) lethargus. Additional time points for RNA collection were in the mid-L4 stage, approximately four hours prior to lethargus, and in the young adult stage, four hours after lethargus. These samples were interrogated with the Affymetrix C. elegans Genome Array. A total of 1,804 gene transcripts were up regulated, and 1,088 gene transcripts were down regulated, during the L4 lethargus period compared to the L4 and Adult stages (false discovery rate (FDR) < 0.05). There were a total of 3 groups and 5x replication for each group, for 15 total samples that were analyzed. The groups were (1) L4, (2) L4-lethargus, (3) Adult. We generated the following pairwise comparisons using R/maanova: L4-lethargus vs L4, L4-lethargus vs Adult. The permutation based p-values for each test were multiplied by 2 and transcripts with an FDRM-bM-^IM-$5% were selected.
Project description:To investigate which genes are up- or down-regulated during L4 sleep in C. elegans mutant aptf-1(gk794) we performed whole genome microarray expression profiling using the C. elegans (V2) Gene Expression Microarray, 4x44K from Agilent Technologies.
Project description:The evolutionarily conserved Wnt/?-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector ?-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/?-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type?specific "mRNA tagging" to enrich for VPC and seam cell?specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type?specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells.