Project description:DNA methylation is a key epigenetic modification regulating genome organization, stability, and gene expression. Stable DNA methylation critically relies on methyl groups provided through folate-mediated one-carbon (C1) metabolism, yet the origin and regulation of C1 supply remain elusive. Here we demonstrate that photorespiration serves as a major C1 source for DNA methylation in Arabidopsis. We show that C1 from formate, a photorespiratory byproduct, is incorporated into 5-methyl-cytosine via the reductive cytosolic folate pathway. This occurs predominantly during the day, negatively regulating serine utilization as alternative C1 source. Consequently, suppression of photorespiration under elevated CO₂ levels alters the DNA methylation landscape, an effect exacerbated when regulation of C1 metabolism by the formate-dependent pathway is impaired. Thus, our findings link the fundamental metabolic process of photorespiration to epigenetic stability, highlighting how rising atmospheric CO₂ levels can induce DNA methylation changes.
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: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: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.