<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mary K Keyes</style></author><author><style face="normal" font="default" size="100%">Hyeran Jang</style></author><author><style face="normal" font="default" size="100%">Joel B. Mason</style></author><author><style face="normal" font="default" size="100%">Zhenhua Liu</style></author><author><style face="normal" font="default" size="100%">Jimmy W Crott</style></author><author><style face="normal" font="default" size="100%">Donald E Smith</style></author><author><style face="normal" font="default" size="100%">Simonetta Friso</style></author><author><style face="normal" font="default" size="100%">Sang-Woon Choi</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Older age and dietary folate are determinants of genomic and p16-specific DNA methylation in mouse colon</style></title><secondary-title><style face="normal" font="default" size="100%">The Journal of Nutrition</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aging</style></keyword><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Colon</style></keyword><keyword><style  face="normal" font="default" size="100%">diet</style></keyword><keyword><style  face="normal" font="default" size="100%">Dietary Supplements</style></keyword><keyword><style  face="normal" font="default" size="100%">Folic Acid</style></keyword><keyword><style  face="normal" font="default" size="100%">Folic Acid Deficiency</style></keyword><keyword><style  face="normal" font="default" size="100%">Gene Expression Regulation</style></keyword><keyword><style  face="normal" font="default" size="100%">Genes</style></keyword><keyword><style  face="normal" font="default" size="100%">Genome</style></keyword><keyword><style  face="normal" font="default" size="100%">Inbred {C57BL</style></keyword><keyword><style  face="normal" font="default" size="100%">Male</style></keyword><keyword><style  face="normal" font="default" size="100%">Mice</style></keyword><keyword><style  face="normal" font="default" size="100%">p16</style></keyword><keyword><style  face="normal" font="default" size="100%">{DNA} Methylation</style></keyword><keyword><style  face="normal" font="default" size="100%">} Time Factors</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/17585020</style></url></web-urls></urls><number><style face="normal" font="default" size="100%">7</style></number><volume><style face="normal" font="default" size="100%">137</style></volume><pages><style face="normal" font="default" size="100%">1713–1717</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Older age and inadequate folate intake are strongly implicated as important risk factors for colon cancer and each is associated with altered {DNA} methylation. This study was designed to determine the effects of aging and dietary folate on select features of {DNA} methylation in the colon that are relevant to carcinogenesis. Old (18 mo; n = 34) and young (4 mo; n = 32) male {C57BL/6} mice were randomly divided into 3 groups and fed diets containing 0, 4.5, or 18 mumol folate/kg (deplete, replete, and supplemented groups, respectively) for 20 wk. Genomic {DNA} methylation and p16 promoter methylation in the colonic mucosa were analyzed by liquid chromatography/electrospray {ionization/MS} and methylation-specific {PCR,} respectively. p16 gene expression was determined by real-time {RT-PCR.} Old mice had significantly lower genomic {DNA} methylation compared with young mice at each level of dietary folate (4.5 +/- 0.2, 4.8 +/- 0.1, and 4.9 +/- 0.1 vs. 6.0 +/- 0.1, 5.3 +/- 0.2, and 5.9 +/- 0.2%, in folate-deplete, -replete, and -supplemented groups, respectively, P {\textless} 0.05) and markedly higher p16 promoter methylation (61.0 +/- 2.7, 69.7 +/- 6.9, and 87.1 +/- 13.4 vs. 10.8 +/- 3.6, 8.4 +/- 1.8, and 4.9 +/- 1.7%, respectively, P {\textless} 0.05). In old mice, genomic and p16 promoter {DNA} methylation each increased in a manner that was directly related to dietary folate {(P(trend)} = 0.009). Age-related enhancement of p16 expression occurred in folate-replete {(P} = 0.001) and folate-supplemented groups {(P} = 0.041), but not in the folate-deplete group. In conclusion, aging decreases genomic {DNA} methylation and increases promoter methylation and expression of p16 in mouse colons. This effect is dependent on the level of dietary folate.</style></abstract><notes><style face="normal" font="default" size="100%">{PMID:} 17585020</style></notes></record></records></xml>