Next Generation Sequencing of bacterial surface-displayed ENAH EVH1 ligand peptides after a FACS titration sort (MassTitr)
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ABSTRACT: We used bacterial surface display and FACS to sort peptide binders to a tetramerized ENAH EVH1 domain at multiple concentrations of ENAH into 4 gates. This experiment was repeated three times. By calculating the distribution of each clone across gates at multiple concentrations, we are able to assess whether a clone exhibited concentration-dependent binding to ENAH EVH1 domain, allowing us to distinguish binders from nonbinders.
Project description:In order to understand the protein interactors of the inhibitory synaptic scaffolding protein gephyrin, we precipitated gephyrin protein complexes from adult mouse brain lysates of both sexes using both a commercial anti-gephyrin antibody (clone 3B11), as well as anti-gephyrin Designed Ankyrin Repeat Domain (DARPin) protein binders.
Project description:G-quadruplex (G4) is non-canonical nucleic acid structure involved in a plethora of fundamental biological processes. In past decades, it has been studied as a promising pharmaceutical target for anticancer therapy. However, no G4-targeting agent has shown significant clinical effects up to date. Pyridostatin (PDS), a well-known G4 binder, can induce double-stranded DNA breaks and genome instability. We have recently shown that Pyridostatin (Pyridostatin) and other G4 binders can trigger micronuclei formation in cancer cells at non-cytotoxic concentrations. As micronuclei can play a crucial role in linking genome instability to innate immunity, we have here wondered whether G4 binders can induce immune gene activation in human MCF-7 breast cancer cells.
Project description:Single-cell RNA-sequencing (scRNA-Seq) is widely used to characterize immune cell populations. However, mRNA levels correlate poorly with expression of surface proteins, which are well established to define immune cell types. CITE-Seq (cellular indexing of transcriptomes and epitopes by sequencing) utilizes oligonucleotide-tagged antibodies to simultaneously analyze surface phenotypes and transcriptomes. Considering the high costs of adding surface phenotyping to scRNA-Seq, we aimed to determine which of 188 tested CITE-Seq antibodies can detect their antigens on human peripheral blood mononuclear cells (PBMCs), a commonly interrogated cell population in immunology, and find the optimal concentration for staining. The recommended concentration was optimal for 76 antibodies, whereas staining quality of 7 antibodies improved when the concentration was doubled. 33 and 8 antibodies still worked well when the concentration was reduced to 1/5 or 1/25, respectively. 64 antigens were not detected at any antibody concentration. Optimizing the antibody panel by removing antibodies not able to detect their target antigens and adjusting concentrations of the remaining antibodies could enable a cost reduction of almost 50%. In conclusion, our data are a resource for building an informative and cost-effective panel of CITE-Seq antibodies and use them at their optimal concentrations in future CITE-seq experiments on human PBMCs.
Project description:The experiment was designed to obtain a broader unbiased view of the changes in islet macrophages following low dose STZ challenge. Mice were purchased from Jackson Laboratory (Bar Harbor, ME). 16-20-week-old C57BL/6J males were given 30 mg/kg STZ or acetate buffer (control) i.p. (intraperitoneal injection) for 5 consecutive days. Following the first STZ or buffer injection mice were sacrificed on day 14 and islets were isolated by collagenase digestion. Freshly isolated islets were dispersed in 0.02% Trypsin-EDTA for 3 minutes followed by up to 1 minute of pipetting under a stereomicroscope to obtain a single cell solution. Islet media was added to stop the reaction. Islets from 10 mice were pooled per sample (N). Dispersed islets were washed with FACS buffer (1% heat inactivated FBS, 1 mM EDTA, 11 mM glucose in PBS). Cells were kept on ice and pre-incubated with Fc Block (1:100) for 5 minutes, followed by 30 min incubation with CD45-eFluor 450 (1:250; clone 30-F11), Ly-6C-APC (1:1,200; clone HK1.4), CD11b-PE (1:1,200; clone M1/700, F4/80-FITC (1:150; clone BM8), CD11c-PECy7 (1:150; clone N418), and the viability dye 7AAD (1:2,000). Unstained, single stains, and fluorescence minus one controls were used for setting gates and compensation. Viable, single CD45+Ly6c-Cd11b+Cd11c+F4/80+ cells were sorted using a BD FACS Aria IIu directly into lysis buffer, and the RNeasy Plus Micro Kit from Qiagen was used to isolate total RNA. Total RNA quality control quantification was performed using an Agilent 2100 Bioanalyzer. All RNA samples had an RNA integrity number (RIN) ≥9.1. The NeoPrep Library Prep System from Ilumina was used for library preparation followed by sequencing using standard Illumina methods and Ilumina NextSeq500.
Project description:Proper chromosome segregation is essential in all living organisms. The ParA-ParB-parS system is widely employed for chromosome segregation in bacteria. Previously, we showed that Caulobacter crescentus ParB requires cytidine triphosphate to escape the nucleation site parS to spread by sliding to the neighboring DNA. Here, we provide the structural basis for this transition from nucleation to spreading by solving co-crystal structures of a C-terminal domain truncated C. crescentus ParB with parS and with a CTP analog. Nucleating ParB is an open clamp, in which parS is captured at the DNA-binding domain (the DNA-gate). Upon binding CTP, the N-terminal domain (NTD) self-dimerizes to close the NTD-gate of the clamp. The DNA-gate also closes, thus driving parS into a compartment between the DNA-gate and the C-terminal domain. CTP hydrolysis and/or the release of hydrolytic products may re-open the gates. Overall, we suggest a CTP-operated gating mechanism that regulates ParB nucleation and spreading.
Project description:The goals of this study were to identify LIN28 downstream gene targets in breast cancer cells. We use a subclone of the MCF-7 breast cancer cell line, MCF-7M as our model system. Methods: mRNA profiles from MCF-7M breast cancer cells treated with siRNA against non-targeting control (NT), LIN28, hnRNP A1, LIN28 and hnRNPA1 (LIN28A1) for 72 hrs were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped over 200 million sequence reads per sample to the human genome (build h19). Each of the four groups had two biological replicates. We developed a custom method to identify alternative splicing events and identified 111 genes with significant (FDR<0.05) differential splicing for LIN28 depleted cells compared to non-targeting siRNA control, as well as 249 and 182 genes for hnRNP A1 and LIN28A1 respectively. RNA-seq data were validated with by qRT–PCR analysis of a subset of genes. Conclusions: Results reveal that LIN28 regulates alternative splicing and steady state mRNA expression of genes implicated in aspects of breast cancer biology. Notably, cells lacking LIN28 undergo significant isoform switching of the ENAH gene, resulting in a decrease in the expression of ENAH exon 11a isoform. Expression of ENAH isoform 11a has been shown to be elevated in breast cancers that express HER2. mRNA profiles of MCF-7M cells treated with siRNA for NT control, LIN28, hnRNP A1, and LIN28 plus hnRNP A1 (A1) (LIN28A1) were generated by deep sequencing, in duplicate, using Illumina HiSeq 2000