Longitudinal epigenetic drift in mice perinatally exposed to lead.
An understanding of the natural change in DNA methylation over time, defined as "epigenetic drift," will inform the study of environmental effects on the epigenome. This study investigates epigenetic drift in isogenic mice exposed perinatally to lead (Pb) acetate at four concentrations, 0 ppm (control), 2.1 ppm (low), 16 ppm (medium), and 32 ppm (high) prior to conception through weaning, then followed until 10 months of age. Absolute values of DNA methylation in a transposon-associated metastable locus, Cdk5-activator binding protein (Cabp(IAP)), and three imprinted loci (Igf2, Igf2r, and H19) were obtained from tail tissue in paired samples. DNA methylation levels in the controls increased over time at the imprinted Igf2 and Igf2r loci (both P = 0.0001), but not at the imprinted H19 locus or the Cabp(IAP) metastable epiallele. Pb exposure was associated with accelerated DNA hypermethylation in Cabp(IAP) (P = 0.0209) and moderated hypermethylation in Igf2r (P = 0.0447), and with marginally accelerated hypermethylation at H19 (P = 0.0847). In summary, the presence and magnitude of epigenetic drift was locus-dependent, and enhancement of drift was mediated by perinatal Pb exposure, in some, but not all, loci.
Department of Environmental Health Sciences; University of Michigan; Ann Arbor, MI USA.
Christopher
C
Faulk
Department of Environmental Health Sciences; University of Michigan; Ann Arbor, MI USA.
Kevin
K
Liu
Department of Environmental Health Sciences; University of Michigan; Ann Arbor, MI USA.
Amanda
A
Barks
Department of Environmental Health Sciences; University of Michigan; Ann Arbor, MI USA.
Jaclyn M
JM
Goodrich
Department of Environmental Health Sciences; University of Michigan; Ann Arbor, MI USA.
Dana C
DC
Dolinoy
D000818:Animals; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D056426:Genetic Loci; D018392:Genomic Imprinting; D007854:Lead / Q000633:toxicity*; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000235:genetics*; D013997:Time Factors
D007854:Lead
DNA methylation; development; drift; environment; environmental epigenomics; epigenetics; plasticity