Project description:Interventions: Phase I Screening and fecal DNA methylation test group:N/A
Primary outcome(s): Detection rate of fecal DNA methylation test in colorectal cancer and precancerous lesions
Study Design: Cross-sectional
Project description:This is a comparative study. This study is to compare the diagnostic sensitivity between circulating tumor DNA methylation and carcinoembryonic antigen in detecting colorectal cancer. There are two steps in this study. Firstly, the diagnostic model is established based on tumor-specific plasma circulating tumor DNA methylation markers. Secondly, the sensitivity, specificity and accuracy of plasma circulating tumor DNA methylation are compared with that of carcinoembryonic antigen in detecting colorectal cancer.
Project description:Study hypothesis: Increasing folate status and the MethyleneTetraHydroFolate Reductase (MTHFR) C677T genotype influence intermediary biomarkers of preclinical neoplasia (DeoxyriboNucleic Acid [DNA] methylation and uracil misincorporation) in human colonic epithelium.
Primary outcome(s): Changes in genomic and gene specific DNA methylation and uracil misincorporation.
Project description:Protein methylation plays important roles in DNA damage signaling. To date, there is still a lack of global profiling of whole-cell methylation changes during the DNA damage response and repair. In this study, using HILIC affinity enrichment combined with MS analysis, we conducted a quantitative analysis of the methylated proteins in HEK293T cells in response to IR-induced DNA damage. In total, 235 distinct methylation sites responding to IR treatment were identified, and 38% of them were previously unknown. Multiple RNA-binding proteins were differentially methylated upon DNA damage stress. Furthermore, we identified 14 novel methylations in DNA damage response-related proteins. Moreover, we validated the function of PARP1 K23 methylation in repairing IR-induced DNA lesions.
Project description:In plants, the maintenance of DNA methylation is controlled by several self-reinforcing loops involving histone methylation and non-coding RNAs. However, how methylation is initially patterned at specific genomic loci is largely unknown. Here, we describe four Arabidopsis REM transcription factors, VDD, VAL, REM12 and REM13, that recognize specific sequence regions, and together with the protein GENETICS DETERMINES EPIGENETICS1 (GDE1), recruit RNA polymerase IV transcription complexes. This targeted recruitment leads to the production of 24-nucleotide small interfering RNAs (24nt-siRNAs) that guide DNA methylation to specific genomic sites in plant female reproductive tissues. In the absence of GDE1, Pol IV transcription complexes are directed to loci bound by an alternative transcription factor, REM8, highlighting the role of REM transcription factors and GDE1 proteins as positional cues for epigenetic modulation. These findings establish a direct connection between sequence-specific transcription factors and the spatial regulation of siRNAs production and DNA methylation, offering refreshed insights into the genetic control of epigenetic patterning.
Project description:Stable inheritance of DNA methylation is critical for maintaining the differentiated phenotypes in multicellular organisms. However, the molecular basis ensuring high fidelity of maintenance DNA methylation is largely unknown. Here, we demonstrate that two distinct modes of DNMT1 recruitment, one is DNA replication-coupled and the other is uncoupled mechanism, regulate the stable inheritance of DNA methylation. PCNA-associated factor 15 (PAF15) represents a primary target of UHRF1 and undergoes dual mono-ubiquitylation (PAF15Ub2) on chromatin. PAF15Ub2 specifically interacts with DNMT1 and controls the recruitment of DNMT1 in a DNA replication-coupled manner. Thus, loss of PAF15Ub2 results in impaired DNA methylation at sites replicating during early S phase. In contrast, outside of S phase or when PAF15 ubiquitylation is perturbed, UHRF1 ubiquitylates histone H3 to promote DNMT1 recruitment. Together, we identify replication-coupled and uncoupled mechanisms of maintenance DNA methylation, both of which collaboratively ensure the stable DNA methylation.
Project description:Southern elephant seals (Mirounga leonine) are marine mammals with extreme diving profiles (300m to 1000m deep for 20 to 30 min). These apnea dives raise the question of muscular adaptations to hypoxia, as the muscles are particularly solicited during these dives. Moreover, exposure to hypoxia followed by reperfusion generally leads to the production of reactive oxygen species with deleterious effects on cells. The oxidative stress response can therefore be triggered in muscle cells during diving, as well as key changes related to cellular energetics. Finally, exposure to hypoxia may differ between juveniles and adults. To answer these questions, we analyzed the muscle proteome of juvenile and adult elephant seals, with the ultimate aim of linking differences with possible differences in antioxidant balance and mitochondrial function.
