Project description:To generate a bona fide model to study post-stress baterial programmed cell death (PCD), we used a temperature-sensitive E. coli mutant (dnaB-Ts) since temperature stress can be rapidly reversed while other stress, such as antibotic treatment, is difficult to be rapidly and completely stopped and removed for post-stress PCD analysis. When cells were shifted from permissive (30 °C) to non-permissive temperature (42 °C), the dnaB-Ts ΔahpC double mutant maintained full surival while survival of the dnaB-Ts single mutant dropped 3 orders of magnitude; similarly, the double mutant showed much higher survival during treatments with quinolones and β-lactams at permissive temperature. The purpose of the RNA-seq analyses is to uncover molecular mechanisms underlying the increased survival of the dnaB-Ts ΔahpC double mutant by comparing its transcriptional profiles with that of the dnaB-Ts single mutant at both permissive and non-permissive temperature. The results showed that multiple antioxidative systems and stress response pathways were highly upregulated due to a deficiency of ahpC when combined with a dnaB-Ts mutation. The high expression of these genes are consistent with the lower levels of toxic reactive oxygen species (ROS) in the dnaB-Ts ΔahpC mutant than in the dnaB-Ts single mutant. Thus, the RNA-seq data supported that ROS are an important lethal factor in bacterial suicide pathways when bacterial cells are exposed to harsh stress.
Project description:Embryonic stem (ES) cells and embryos reversibly pause via chemical mTOR inhibition. In this study, we investigate the tissue-specific response to mTORi-induced pausing in ES and trophoblast stem (TS) cells. To resolve the sequential rewiring of the proteome, we conducted a time-series proteomics experiment at 1, 3, 6, 12, 24, and 48 hours upon induction of pausing, and at 1, 3, 6, 12, 24, and 48 hours upon release of pausing in ES and TS cells. We find that ES, but not TS cells pause reversibly. To optimise developmental pausing conditions, we reasoned that by understanding the difference in pausing response of ES and TS cells, we could identify which pathways are essential for pausing. We found that KEGG pathways related to amino acid degradation, fatty acid degradation, and DNA repair are upregulated in ES cells, but downregulated in TS cells during entry into pausing. Moreover, by targeted metabolomics, we found a depletion of short chain carnitines in the paused ES cells. To extend the length of developmental pausing, we supplemented paused embryos with L-carnitine. The L-carnitine supplementation facilitates lipid usage and prolongs the pausing length by 19 days through the establishment of a more dormant state.
Project description:Analysis of high-throughput transcriptome sequencing (RNA-seq) data often observed numerous 'non-co-linear' (NCL) transcripts, which may originate from genetic rearrangements (gene fusion) indicated the importance of fusion events and circRNAs in carcinogenesis; however, the role of ts-RNAs remains largely uninvestigated. Here we developed a hybrid sequencing pipeline ("NCLscan-hybrid"), which integrated different types of short (Illumina-based) and extra-long (PacBio-based) RNA-seq data to eliminate potential false positives from experimental artifacts, fusion events, and circRNAs. We applied NCLscan-hybrid to investigate of ts-RNAs in human breast cancer, the most malignant tumors diagnosed in women worldwide. Through multiple experimental validation steps, we confirmed that the intragenic ts-RNA, ts-ARFGEF1, was highly expressed in breast cancer cells but absent in normal breast cells. Furthermore, we experimentally validated that ts-ARGEF1 can contribute to cell proliferation and apoptosis. Analysis of xenograft in nude mice showed that disruption of ts-ARFGEF1 expression can significantly attenuate tumor growth. Microarray analysis revealed that ts-ARFGEF1 knockdown could trigger PERK/ATF4/CHOP signaling pathway, implying the function of ts-ARFGEF1 in ER homeostasis. Taken together, our findings provide an in-depth view of the true complexity of intragenic NCL events and, for the first time, show further insight into the potential roles of intragenic ts-RNAs in tumor cell development.
Project description:Analysis of high-throughput transcriptome sequencing (RNA-seq) data often observed numerous 'non-co-linear' (NCL) transcripts, which may originate from genetic rearrangements (gene fusion) indicated the importance of fusion events and circRNAs in carcinogenesis; however, the role of ts-RNAs remains largely uninvestigated. Here we developed a hybrid sequencing pipeline ("NCLscan-hybrid"), which integrated different types of short (Illumina-based) and extra-long (PacBio-based) RNA-seq data to eliminate potential false positives from experimental artifacts, fusion events, and circRNAs. We applied NCLscan-hybrid to investigate of ts-RNAs in human breast cancer, the most malignant tumors diagnosed in women worldwide. Through multiple experimental validation steps, we confirmed that the intragenic ts-RNA, ts-ARFGEF1, was highly expressed in breast cancer cells but absent in normal breast cells. Furthermore, we experimentally validated that ts-ARGEF1 can contribute to cell proliferation and apoptosis. Analysis of xenograft in nude mice showed that disruption of ts-ARFGEF1 expression can significantly attenuate tumor growth. Microarray analysis revealed that ts-ARFGEF1 knockdown could trigger PERK/ATF4/CHOP signaling pathway, implying the function of ts-ARFGEF1 in ER homeostasis. Taken together, our findings provide an in-depth view of the true complexity of intragenic NCL events and, for the first time, show further insight into the potential roles of intragenic ts-RNAs in tumor cell development.
Project description:To evaluate the immunological landscape of PRDM1-crRNA CAR-Ts, we performed timecourse RNAseq. We also compared and contrasted transcription profiles of CAR-Ts mutated by two different PRDM1-crRNAs.