ABSTRACT: 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 understand 4-TU labelling kinetics in a novel zebrafish transgenic line (lf:UPRT), we exposed adult lf:UPRT zebrafish (whereby animals have hepatocyte-specific uracil phosphoribosyltransferase expression) with 4-TU for 1, 3, 6 and 9 hours. We then dissected adult livers for SLAM-ITseq to determine the optimal 4-TU labelling time in our SLAM-ITseq workflow to allow us to study hepatocyte-specific nascent transcriptional changes.
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:Total RNA was extracted from about 10, 1-week or 5-weeks old, entire or dissected (head, legs, wings and ovaries removed) adult flies, using TRIzol reagent (Invitrogen) following manufacturer’s instructions. The following genotypes dedicated for TU-tagging cell - specific transcript isolation were used: Hand>LacZ;HA-UPRT, Hand>MblRNAi;HA-UPRT, Hand>Bru3;HA-UPRT and Hand>960CTG;HA-UPRT
Project description:We show that the combination of spatially restricted uracil phosphoribosyltransferase (UPRT) expression with 4-thiouracil (4TU) delivery can be used to label and purify cell type specific RNA from intact complex tissues. This method is useful for isolating RNA from cell types that are difficult to isolate by dissection or dissociation methods and should work in any organism where UPRT can be spatially expressed, including mammals and other vertebrates. To confirm that thio-labeled RNA was from UPRT-expressing cells and demonstrate the utility of TU-tagging for cell type-specific RNA isolation, we purified TU-tagged and untagged RNA and compared them using microarrays. We chose to isolate RNA from larval glia, which are present in low number, are highly dispersed, and have a complex cell morphology, making them one of the most difficult cell types to isolate by dissection or dissociation methods. We used reversed polarity (repo)-GAL4 to drive expression of UAS-UPRT specifically in glial cells of the larval brain. We purified TU-tagged and untagged RNA from 72-96h larval brains, and hybridized them to custom Agilent microarrays. We performed two biological replicate experiments.
Project description:We developed a knock-in mouse line that combines four enrichment tools to study gene regulatory networks of the brain and other complex tissues. As a result, chromatin, nascent RNA, translating mRNA and mature miRNA can be purified from specific cell populations. Specifically, we developed "Tagger" – a Cre and/or Flp recombinase-dependent mouse model that expresses four proteins to enable purification of distinct populations of cellular nucleic acids from specific cell types. Upon activation by cell type-directed recombinases, cells of a desired population express: 1) exogenous uracil phoshoribosyltransferase (UPRT) for tagging nascent total RNA with thiol groups upon administration of 4-thiouracil (4TU, TU-Tag), 2) epitope-tagged large ribosomal subunit protein 22 (Rpl22) to co-immunoprecipitate (co-IP) ribosome-bound mRNA (RiboTag), 3) epitope-tagged Argonaute 2 (Ago2, a component of the RNA-induced silencing complex) to co-IP mature miRNA (AgoTag), and 4) nucleus-directed mKate2 red fluorescent protein, providing good tissue penetrating transmission properties for in vivo imaging and a fluorescent nuclear tag (NucTag) for FACS enrichment of nuclei for chromatin studies.
Project description:We developed a knock-in mouse line that combines four enrichment tools to study gene regulatory networks of the brain and other complex tissues. As a result, chromatin, nascent RNA, translating mRNA and mature miRNA can be purified from specific cell populations. Specifically, we developed "Tagger" – a Cre and/or Flp recombinase-dependent mouse model that expresses four proteins to enable purification of distinct populations of cellular nucleic acids from specific cell types. Upon activation by cell type-directed recombinases, cells of a desired population express: 1) exogenous uracil phoshoribosyltransferase (UPRT) for tagging nascent total RNA with thiol groups upon administration of 4-thiouracil (4TU, TU-Tag), 2) epitope-tagged large ribosomal subunit protein 22 (Rpl22) to co-immunoprecipitate (co-IP) ribosome-bound mRNA (RiboTag), 3) epitope-tagged Argonaute 2 (Ago2, a component of the RNA-induced silencing complex) to co-IP mature miRNA (AgoTag), and 4) nucleus-directed mKate2 red fluorescent protein, providing good tissue penetrating transmission properties for in vivo imaging and a fluorescent nuclear tag (NucTag) for FACS enrichment of nuclei for chromatin studies.
Project description:We developed a knock-in mouse line that combines four enrichment tools to study gene regulatory networks of the brain and other complex tissues. As a result, chromatin, nascent RNA, translating mRNA and mature miRNA can be purified from specific cell populations. Specifically, we developed "Tagger" – a Cre and/or Flp recombinase-dependent mouse model that expresses four proteins to enable purification of distinct populations of cellular nucleic acids from specific cell types. Upon activation by cell type-directed recombinases, cells of a desired population express: 1) exogenous uracil phoshoribosyltransferase (UPRT) for tagging nascent total RNA with thiol groups upon administration of 4-thiouracil (4TU, TU-Tag), 2) epitope-tagged large ribosomal subunit protein 22 (Rpl22) to co-immunoprecipitate (co-IP) ribosome-bound mRNA (RiboTag), 3) epitope-tagged Argonaute 2 (Ago2, a component of the RNA-induced silencing complex) to co-IP mature miRNA (AgoTag), and 4) nucleus-directed mKate2 red fluorescent protein, providing good tissue penetrating transmission properties for in vivo imaging and a fluorescent nuclear tag (NucTag) for FACS enrichment of nuclei for chromatin studies.
Project description:We developed a knock-in mouse line that combines four enrichment tools to study gene regulatory networks of the brain and other complex tissues. As a result, chromatin, nascent RNA, translating mRNA and mature miRNA can be purified from specific cell populations. Specifically, we developed "Tagger" – a Cre and/or Flp recombinase-dependent mouse model that expresses four proteins to enable purification of distinct populations of cellular nucleic acids from specific cell types. Upon activation by cell type-directed recombinases, cells of a desired population express: 1) exogenous uracil phoshoribosyltransferase (UPRT) for tagging nascent total RNA with thiol groups upon administration of 4-thiouracil (4TU, TU-Tag), 2) epitope-tagged large ribosomal subunit protein 22 (Rpl22) to co-immunoprecipitate (co-IP) ribosome-bound mRNA (RiboTag), 3) epitope-tagged Argonaute 2 (Ago2, a component of the RNA-induced silencing complex) to co-IP mature miRNA (AgoTag), and 4) nucleus-directed mKate2 red fluorescent protein, providing good tissue penetrating transmission properties for in vivo imaging and a fluorescent nuclear tag (NucTag) for FACS enrichment of nuclei for chromatin studies.