title: Measurements of DNA methylation at seven loci in various tissues of CD1 mice.
abstract: In humans, considerable variation in methylation at single loci and repetitive elements in various cells and tissues is observed. Recently, several inter- and intra-tissue correlations for DNA methylation have been reported. To investigate the extent and reproducibility of such correlations, we investigated inter- and intra-tissue methylation correlations among seven different loci in 9 different tissues in a population of 100 healthy seven-week-old CD1 outbred mice. We used a highly quantitative approach to measure methylation levels to high accuracy at two single loci in the alpha-actin and myosine light chain promoters, at three differentially methylated regions of the Peg3, Snrpn and Lit1 genes associated with imprinted loci, and at two repetitive elements in the Line-1 and IAP-LTR genes in the various tissues. In this population of mice, methylation at several loci was sex-associated and intra-tissue correlations among the studied loci were observed for brain and spleen. Inter-tissue correlations were rarely observed. To investigate method-dependent experimental variability, we re-analyzed the same spleen and tongue samples using SIRPH and pyrosequencing methods and reconfirmed intra-tissue correlations for spleen and sex-associated correlations for DNA methylation for tongue. When we repeated DNA methylation measurements for a second mouse population raised under similar conditions three months later, we did not detect sex-associated or intra-tissues correlations. Additional studies that examine large numbers of loci may be required to further understand the factors that influence stability of DNA methylation.
authors.affiliation: Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Bonn, Germany.
authors.forename: Laurynas
authors.initials: L
authors.lastname: Daugela
authors.forename: Nicole
authors.initials: N
authors.lastname: Nüsgen
authors.forename: Maja
authors.initials: M
authors.lastname: Walier
authors.forename: Johannes
authors.initials: J
authors.lastname: Oldenburg
authors.forename: Rainer
authors.initials: R
authors.lastname: Schwaab
authors.forename: Osman
authors.initials: O
authors.lastname: El-Maarri
mesh_terms: D000818:Animals; D019175:DNA Methylation; D051379:Mice; D008815:Mice, Inbred Strains