Project description:ATF6 is a key regulator of the unfolded protein response. Through use of zebrafish and cultured cells we demonstrate that ATF6 drives fatty liver disease by interaction with fatty acid synthase (FASN). Total small RNA from livers of 5 dpf larval zebrafish were collected: 2 batches of Tg(fabp10:nls-mCherry) control larvae, 2 batches of ethanol-treated Tg(fabp10:nls-mCherry) larvae, and 1 batch of Tg(fabp10:nAtf6-cherry; cmlc2:GFP). Each batch was purified for preparation of high-throughput sequencing libraries.
Project description:Mobile elements are important evolutionary forces that challenge genomic integrity. Long interspersed element-1 (L1, also known as LINE-1) is the only autonomous transposon still active in the human genome. It displays an unusual pattern of evolution, with at any given time a single active L1 lineage amplifying to thousands of copies before getting replaced by a new lineage likely under pressure of host restriction factors, which act notably by silencing L1 expression during early embryogenesis. Here, we demonstrate that in human embryonic stem cells (hESC) KAP1, the master co-factor of KRAB-containing zinc finger proteins (KRAB-ZFP) previously implicated in the restriction of endogenous retroviruses, represses a discrete subset of L1 lineages predicted to have entered the ancestral genome between 26.8 and 7.6 million years ago. In the mouse, we documented a similar chronologically conditioned pattern, albeit with a much contracted time scale. We could further identify an L1-binding KRAB-ZFP, suggesting that this rapidly evolving protein family is more globally responsible for L1 recognition. KAP1 knockdown in hESC induced the expression of KAP1-bound L1 elements, but their younger, human-specific counterparts (L1Hs) were unaffected. Instead, they were stimulated by depleting DNA methyltransferases, consistent with recent evidence demonstrating that the PIWI-piRNA pathway regulates L1Hs in hESC. Altogether, these data indicate that the early embryonic control of L1 is an evolutionary dynamic process, and support a model whereby newly emerged lineages are first suppressed by DNA methylation-inducing small RNA-based mechanisms, before KAP1-recruiting protein repressors are selected. HA-tagged Gm6871 ChIP-seq in mES cells, RNA-seq in control and Gm6871 KD mES cells, KAP1 ChIP-seq in WT mES cells, RNA-seq in control and DNMTs KD hES cells.
Project description:Glioblastoma is the most common, aggressive tumor of CNS, with a 5-year overall survival rate of 5%. The treatment is challenging due to its location and the inevitable recurrence in 80% of the cases. To understand the cause behind this recurrence, we established an in vitro radiation survival model that mimics clinical scenarios. GBM Parent (P) cells, after being given a lethal dose of radiation, undergo tremendous cell death but leave behind a small residual surviving population that shows senescence phenotype. These residual (RS) cells eventually reverse from senescence (End of senescence) and give rise to aggressive relapse (R). To find molecular players behind this reversal of senescence, we carried out RNA sequencing of GBM cell lines U87MG and SF268 at mentioned stages of senescence post-radiation treatment.
Project description:Reverse transcription-derived sequences account for at least half of the human genome. Although these retroelements are formidable motors of evolution, they can occasionally cause disease, and accordingly are inactivated during early embryogenesis through epigenetic mechanisms. In the mouse, at least for endogenous retroviruses, important mediators of this process are the tetrapod-specific KRAB-containing zinc finger proteins (KRAB-ZFPs) and their cofactor TRIM28. The present study demonstrates that KRAB/TRIM28-mediated regulation is responsible for controlling a very broad range of human-specific endogenous retroelements (EREs) in human embryonic stem (ES) cells and that it exerts, as a consequence, a marked effect on the transcriptional dynamics of these cells. It further reveals reciprocal dependence between TRIM28 recruitment at specific families of EREs and DNA methylation. It finally points to the importance of persistent TRIM28-mediated control of ERE transcriptional impact beyond their presumed inactivation by DNA methylation. Analyses of epigentic effectors and marks in KAP1 WT and KD human embryonic stem cells
Project description:We performed an experimental Cas13d-SARScov2 genome-wide screen to identify gRNAs that would allow Cas13d to degrade the viral RNA. We built mCherry reporter plasmids that express mCherry with a 3kb 3'UTR deriving from the SARScov2 genome. In total we designed 11 reporters covering the entire plus strand of the viral genome and 11 other reporters covering the entire minus strand. Each of the 22 mCherry reporter plasmids carries a U6 expression cassette containing a Cas13d gRNA that targets the 3'UTR of the mCherry reporter. Each reporter is represented by a pool of reporters each containing a different gRNA that targets mCherry 3'UTR for a total average of ~300 gRNA per 3'UTR. The entire pool of 22 reporters, each with a pool of ~300 different gRNAs constitutes a comprehensive set ~6,500 reporters (~ 6,500 different gRNAs) that allowed us to interrogate the entire SARScov2 plus and minus strand viral RNA for regions of vulnerability and targetability. In order to specifically interrogate Cas13d activity an remove the biases that would be introduced in the reporter expression by the presence of a large 3kb 3'UTR we used a case (presence of Cas13d) control (absence of Cas13d) design. Briefly, the ~6,500 reporters were lentiviral transduced in RKO cells, the cells were split in 2 populations, 1 population was transduced with Cas13d and the other serving as control did not. The population expressing Cas13d was FACS sorted in low mCherry (efficient gRNAs) and high mCherry (un-efficient gRNAs) in 2 biological replicates and the genomic DNA of these populations was extracted, gRNAs were PCR amplified and sequenced. For the population that did not express Cas13d, a low mCherry, one high mCherry and unsorted population were sequenced as control libraries.
Project description:Morphogenesis requires the dynamic regulation of gene expression, including transcription, mRNA maturation and translation. Dysfunction of general components of the splicing machinery can cause surprisingly specific phenotypes, but the basis for these cell-type specific effects is not clear. Here we show that the faint sausage (fas) locus, implicated in epithelial morphogenesis and previously reported to encode a secreted immunoglobulin domain protein, in fact encodes a subunit of the Prp19 complex that is essential for efficient pre-mRNA splicing. Loss of zygotic fas function impairs the efficiency of splicing, associated with widespread retention of introns in mature mRNAs and dramatic changes in gene expression. Surprisingly, despite these general effects, zygotic fas mutants show specific defects in tracheal cell migration. Zygotic fas function becomes essential during late embryogenesis when maternally supplied splicing factors decline. We propose that tracheal branching, which relies on dynamic changes in gene expression, is particularly sensitive for efficient spliceosome function. Our results provide an entry point to study functions of splicing during organogenesis and provide a better understanding of specific disease phenotypes associated with mutations in general splicing factors.
Project description:Hundreds of immune cell types work in coordination to maintain tissue homeostasis. Upon infection, dramatic changes occur with the localization, migration and proliferation of the immune cells to first alert the body of the danger, confine it to limit spreading, and finally extinguish the threat and bring the tissue back to homeostasis. Since current technologies can follow the dynamics of only a limited number of cell types, we have yet to grasp the full complexity of global in vivo cell dynamics in normal developmental processes and disease. Here we devise a computational method, digital cell quantification (DCQ), which combines genomewide gene expression data with an immune cell compendium to infer in vivo dynamical changes in the quantities of 213 immune cell subpopulations. DCQ was applied to study global immune cell dynamics in mice lungs at ten time points during a 7-day time course of flu infection. We find dramatic changes in quantities of 70 immune cell types, including various innate, adaptive and progenitor immune cells. We focus on the previously unreported dynamics of four immune dendritic cell subtypes, and suggest a specific role for CD103+CD11b- cDCs in early stages of disease and CD8+ pDC in late stages of flu infection. To better understand the physiological role of these differential dynamic changes in the DCs, we measured the genome-wide RNA expression of all four DC subpopulations from lung of influenza infected mice at four time points following infections (two mice per time-point). For sorting dendritic cells from lungs, the lungs from infected and control uninfected C57BL/6J mice were immersed in cold PBS, cut into small pieces in 5 ml DMEM media containing 10% Bovine Fetal Serum, the cell suspensions were grinded using 1ml syringe cup on a 70 μm cell strainers (BD Falcon). The cells were washed with ice cold PBS. Remaining red blood cells were lysed using ammonium chloride solution (Sigma). Cells were harvested, immersed 1ml FACS buffer [PBS+2% FBS, 1mM EDTA], Fc receptors were blocked with anti-mouse CD16/CD32, washed with FACS buffer and divided into two tubes for sorting cDC and pDC cells.