Transgene-induced CCWGG methylation does not alter CG methylation patterning in human kidney cells

Several reports suggest that C(m)CWGG methylation tends not to co-exist with (m)CG methylation in human cells. We have asked whether or not methylation at CCWGG sites can influence CG methylation. DNA from cells expressing an M.EcoRII–GFP fusion was actively methylated at CCWGG sites. CG methylation as measured by R.HpaII/R.MspI ratios was unchanged in cells expressing the transgene. Cloned representatives of C(m)CWGG methylated DNA often contained, or were adjacent to an ALU repeat, suggesting that M.EcoRII-GFP actively methylated gene-rich R-band DNA. The transgenic methyltransferase applied C(m)CWGG methylation to a representative human promoter that was heavily methylated at CG dinucleotides (the SERPINB5 promoter) and to a representative promoter that was essentially unmethylated at CG dinucleotides (the APC promoter). In each case, the CG methylation pattern remained in its original state, unchanged by the presence of neighboring C(m)CWGG sites. Q-PCR measurements showed that RNA expression from the APC gene was not significantly altered by the presence of C(m)CWGG in its promoter. Kinetic studies suggested that an adjacent C(m)CWGG methylation site influences neither the maintenance nor the de novo methylation activities of purified human Dnmt1. We conclude that C(m)CWGG methylation does not exert a significant effect on CG methylation in human kidney cells

Manual de procedimientos mercantiles para disolución y liquidación de sociedades de Capital Variable

El propósito de la investigación fue proporcionar a los egresados, la informaron necesaria contenida en un manual, que permitirá un conocimiento de cada paso de los procesos de disolución y liquidación de sociedades anónimas de capital variabl

Plasma B vitamins and LINE-1 DNA methylation in leukocytes of patients with a history of colorectal adenomas

Item does not contain fulltextSCOPE: Low concentrations of folate, other B vitamins, and methionine are associated with colorectal cancer risk, possibly by changing DNA methylation patterns. Here, we examine whether plasma concentrations of B vitamins and methionine are associated with methylation of long interspersed nuclear element-1 (LINE-1) among those at high risk of colorectal cancer, i.e. patients with at least one histologically confirmed colorectal adenoma (CRA) in their life. METHODS AND RESULTS: We used LINE-1 bisulfite pyrosequencing to measure global DNA methylation levels in leukocytes of 281 CRA patients. Multivariable linear regression was used to assess associations between plasma B vitamin concentrations and LINE-1 methylation levels. Plasma folate was inversely associated with LINE-1 methylation in CRA patients, while plasma methionine was positively associated with LINE-1 methylation. CONCLUSION: This study does not provide evidence that in CRA patients, plasma folate concentrations are positively related to LINE-1 methylation in leukocytes but does suggest a direct association between plasma methionine and LINE-1 methylation in leukocytes

Dietary Patterns Are Associated with Levels of Global Genomic DNA Methylation in a Cancer-Free Population12

Animal studies have provided direct evidence that dietary factors induce changes in DNA methylation patterns. In humans, studies on diet and DNA methylation have yielded inconsistent findings. Because humans tend to consume foods and nutrients that are highly interrelated, study of dietary patterns may have improved the power of detecting the effect of diet on DNA methylation. Using data collected from 149 participants aged 45–75 y in the North Texas Healthy Heart Study, we examined the relationship between dietary patterns and levels of genomic DNA methylation in peripheral blood leukocytes. Dietary data were collected from study participants using the Block FFQ. Genomic DNA methylation was measured using bisulfite conversion of DNA and real-time PCR (MethyLight) for LINE-1. Two dietary patterns were identified using factor analysis: a “prudent” dietary pattern characterized by a high intake of vegetables and fruits, and a “Western” dietary pattern characterized by a high intake of meats, grains, dairy, oils, and potatoes. The prudent dietary pattern was associated with a lower prevalence of DNA hypomethylation (Q4 vs. Q1; OR = 0.33, 95% CI: 0.12–0.92) and the association was dose dependent (P-trend = 0.04). There was no apparent association between the Western dietary pattern and global leukocyte DNA methylation (Q4 vs. Q1; OR = 1.28, 95% CI: 0.47–3.47; P-trend = 0.55). Thus, a dietary pattern characterized by a high intake of vegetables and fruits may protect against global DNA hypomethylation. Future studies with a larger sample size need to confirm that this association holds longitudinally