Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. We carry out 5-hydroxymethylation DNA immunoprecipitation (hmeDIP) prior to sequencing Ion Proton P1 to report on the genome-wide 5hmC patterns. Heterozygote pairs of Tet1 B6;129S4-Tet1tm1.1Jae/J mice were bought from The Jackson Laboratory (Maine USA). Heterozygotes were interbred to produce homozygous knock out males with colony mate wild type controls. Genome-wide 5hmC patterns were generated by hydroxymethyl-DNA immuoprecipitation (hmeDIP) followed by genome wide sequencing on the Ion Proton P1 sequencer.
Project description:The mitochondrial ATP synthase is a macromolecular motor that uses the proton gradient to generate ATP. Proper ATP synthase function requires a stator linking the catalytic and rotary portions of the complex. However, sequence-based searches fail to identify genes encoding stator subunits in apicomplexan parasites like Toxoplasma gondii or the related organisms that cause malaria. Here, we identify 11 previously unknown subunits from the Toxoplasma ATP synthase, which lack homologs outside the phylum. Hidden Markov modeling suggests that two of them—ICAP2 and ICAP18—share distant homology with mammalian stator subunits. Our mass spcetrometry analysis indicates that both proteins form part of the ATP synthase complex.
Project description:In eukaryotic cells, inefficient splicing is surprisingly common and leads to degradation of transcripts with retained introns. How pre-mRNAs are committed to nuclear decay is unknown. Here we uncover a mechanism by which intronic transcripts are targeted for nuclear degradation in fission yeast. Surprisingly, sequence elements within âsuicidalâ introns co-transcriptionally recruit the exosome adaptor Mmi1 not only to degrade unspliced precursor, but also to downregulate levels of the resulting mRNA. Under conditions permissive for fast splicing, Mmi1 is no longer recruited and negative expression regulation is relieved. This mechanism negatively regulates levels of the RNA-helicase DDX5/Dbp2 to ensure cell survival in response to stress. We propose that suicidal introns are maintained because they facilitate regulation of gene expression. We identify multiple novel Mmi1 targets including mRNAs, non-coding RNAs, and sn/snoRNAs. We suggest a general role in RNA regulation for Mmi1 beyond degradation of meiotic transcripts. Two biological replicates of CRAC experiments (Control and Mmi1-HTP). Six RNAseq datasets in total: three biological replicates of wt and delta Mmi1 strain.
Project description:Background: Steatotic liver disease associated with metabolic dysfunction (MASLD) affects up to about 30% of the general adult population and is closely related to obesity and the metabolic syndrome. Cortisol, a stress-related hormone contributing to hepatic fat accumulation and insulin resistance, also promotes progression of the disease. The study aims to investigate the impact of lifestyle modifications on cortisol levels and hepatic steatosis in patients with MASLD. Methods: In a 16-week three-arm randomized trial, 42 patients were randomly assigned to three groups who received dietary advice (CG), dietary advice combined with aerobic exercise (AE + DA), or dietary advice with high-intensity interval training (HIIT + DA). Before the start, after 2 months of intervention, and at the end of the project, medical evaluations, routine biochemical assessments, and psychological questionnaires were analyzed. At baseline and at the end of 4 months, hepatic steatosis was evaluated by Fibroscan®. Results: In the study population, severe hepatic steatosis (74%) and obesity (98%) were prevalent at the beginning of the study. A statistically significant (p-value = 0.001) reduction in circulating cortisol levels was observed over time in the two groups doing exercise, especially in HIIT + DA (p-value = 0.006). Hepatic steatosis, assessed by Fibroscan®, disappeared in 10 participants (CAP value < 248, p-value = 0.003). CAP values and waist circumference decreased in all groups, statistically significantly in the AE + DA group (p-value = 0.005; p-value = 0.04, respectively). Conclusions: The study emphasizes the benefits of combining diet and exercise in managing MASLD. HIIT + DA significantly decreased cortisol levels, while AE + DA was the most potent intervention for reducing hepatic steatosis.
Project description:In order to identify how MnTE-2-PyP affects p300 association to chromatin genome-wide, we performed a p300 chromatin Immunoprecipitation assay followed by Next Generation Sequencing on PC3 cells treated with or without MnTE-2-PyP one hour post-irradiation (Figure 3A). Based on the called peaks near genes, we predicted that HIF-1βand CREB transcription factors were associating DNA less in the presence of MnTE-2-PyP. DNA was ChIP-Fixed from Pc3 cells treated with 20 Gy radiation and with and without T2E drug. There are 2 biological replicates of PC3 untreated cells and 3 biological replicates of PC3 cells treated with MnTE-2-PyP. There are two corresponding input samples for the biological replicates.
Project description:Background and aims: A coordinated stress and regenerative response is important following hepatocyte damage. Here, we investigate the phenotypes that result from genetic abrogation of individual components of the CHK2/ p53/ p21 pathway in a murine model of metabolic liver injury. Methods: NTBC was reduced or withdrawn in Fah / mice lacking Chk2, p53 or p21, and survival, tumor development, liver injury and regeneration were analyzed. Partial hepatectomies were performed and mice were challenged with the Fas-antibody Jo2. Results: In a model of metabolic liver injury, loss of p53, but not of Chk2, impairs the oxidative stress re-sponse and aggravates liver damage, indicative of a direct p53-dependent protective effect on hepatocytes. Cell cycle control during chronic liver injury critically depends on the presence of both p53 and its downstream effector p21. In p53-deficient hepatocytes, unchecked proliferation occurs despite a strong induction of p21, revealing a complex interdependency between p21 and p53. The increased regenerative potential in the absence of p53 cannot fully compensate the surplus injury and is not sufficient to promote survival. Despite the different phenotypes as-sociated with the loss of individual components of the DNA damage response, gene expression patterns are dominated by the severity of liver injury, but reflect distinct effects of p53 on prolif-eration and the anti-oxidative stress response. Conclusion: Characteristic phenotypes result from the genetic abrogation of individual components of the DNA damage response cascade in a liver injury model. The extent to which loss of gene function can be compensated, or affects injury and proliferation, depends on the level at which the cas-cade is interrupted.
Project description:To demonstrate that the P. multistriata gene MRP3 is responsible for sex determination, we overexpressed it in a mating type minus strain. The transgenic strain generated displayed sex reversal and behaved like a strain of the opposite mating type. In this study, we compared the gene expression profile of the wild type versus the transformed strain.
Project description:Smyd3 is a histone methyltransferase implicated in tumorigenesis. Here we show that Smyd3 expression in mice is required but not sufficient for chemically induced liver and colon cancer formation. In these organs Smyd3 is functioning in the nucleus as a direct transcriptional activator of several key genes involved in cell proliferation, epithelial-mesenchymal transition, JAK/Stat3 oncogenic pathways, as well as of the c-myc and b-catenin oncogenes. Smyd3 specifically interacts with H3K4Me3-modified histone tails and is recruited to the core promoter regions of many but not all active genes. Smyd3 binding density on target genes positively correlates with increased RNA Pol-II density and transcriptional outputs. The results suggest that Smyd3 is an essential transcriptional potentiator of a multitude of cancer-related genes. Standard Smyd3-deficient (Smyd3-KO) mice were generated using gene-trap ES cell clones (AS0527 from International Gene Trap Consortium), in which a selection cassette, containing the splice acceptor site from mouse EN2 exon 2 followed by the beta-galactosidase and neomycin resistance gene fusion gene and the SV40 polyadenylation sequence was inserted into the 5th intron of the Smyd3 gene. The resulting mice were devoid of Smyd3 mRNA and protein in all tissues, including liver and colon. For the generation of Smyd3-Tg mice the open reading frame of the mouse Smyd3 cDNA, which contained 3 Flag epitopes at the 3â end was inserted into the StuI site of the pTTR1-ExV3 plasmid (Yan et al, 1990). The 6.8 kb HindIII fragment containing the mouse transthyretin enhancer/promoter, intron 1, Smyd3 cDNA, three Flag epitopes and SV40 poly-A site was used to microinject C57Bl/6 fertilized oocytes. Founder animals were identified by Southern blotting and crossed with F1 mice to generate lines. Specific overexpression in the liver was tested by RT-PCR analysis in different tissues.
Project description:Background & aimsLIM-domain-binding (Ldb) proteins have been demonstrated to be essential not only to key embryonic developmental processes but also to carcinogenesis. We have previously demonstrated Ldb1 to be of high biological and developmental relevance, as a targeted deletion of the Ldb1 gene in mice results in an embryonic lethal and pleiotropic phenotype.MethodsWe have now established a liver-specific Ldb1 knock out to investigate the role of Ldb1 in carcinogenesis, in particular in hepatocellular carcinoma (HCC) development, in vivo.ResultsThese mice demonstrated a significantly enhanced growth of liver cancer by means of tumor size and number, advocating for an essential role of Ldb1 in HCC development. In addition, proliferation and resistance against apoptosis were increased. In order to identify the functional disturbances due to a lack of Ldb1, we performed a 15k mouse gene microarray expression analysis. We found the Myc oncogene to be regulated in the microarray analysis and were able to further confirm this regulation by demonstrating an over-expression of its downstream target Cyclin D1. Furthermore, we were able to demonstrate a down-regulation of the tumor suppressor p21. Finally, the liver stem cell marker EpCAM was also identified to be over expressed in Ldb1(-/-) knock out mice.ConclusionsWe have established a significant role of Ldb1 in cancer development. Furthermore, we provided evidence for a myc/cyclin D1, p21, and EpCAM-dependent signalling to be key downstream regulators of this novel concept in HCC development.