Neonatal exposure to diethylstilbestrol alters the expression of DNA methyltransferases and methylation of genomic DNA in the epididymis of mice.
Fetal and neonatal exposure to diethylstilbestrol (DES) is known to cause many abnormalities, such as cancer, in the male and female reproductive tracts later in life, and epigenetic mechanisms, such as DNA methylation, may be involved in these processes. In the present study, newborn C57BL/6 male mice were exposed to 3 mug of DES from postnatal days 1 to 5. Subsequently, the expression levels of the DNA methyltransferases Dnmt1, Dnmt3a and Dnmt3b and the transcription factors Sp1 and Sp3, which have been reported to regulate the expression of Dnmts, were examined at days 5, 14 and 30. Furthermore, restriction landmark genomic scanning (RLGS), which can analyze genome-wide DNA methylation, was performed to clarify whether or not aberrant DNA methylation was present in the epididymis of the DES-treated mice at day 30. Increased expression of Dnmt3b was observed at days 5 and 14, followed by increased expression of Dnmt1 and Dnmt3a at day 30, as evaluated by real-time RT-PCR. The expression of Sp1 was also increased at day 30. The RLGS analysis revealed that 7 loci of the genomic DNA were demethylated and 1 locus was methylated in the epididymis of the DES-treated mice. Four of these loci specifically demethylated in DES-treated mice were cloned, and all were found to be located within CpG islands near genes. In conclusion, our results indicated the possibility that DES-induced abnormalities of reproductive organs are associated with altered expression levels of DNA methyltransferases and DNA methylation.
Sato
Koji
K
Department of Bioenvironmental Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
Fukata
Hideki
H
Kogo
Yasushi
Y
Ohgane
Jun
J
Shiota
Kunio
K
Mori
Chisato
C
D000818:Animals; D000831:Animals, Newborn; D002874:Chromosome Mapping / Q000379:methods; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects*; D000090205:DNA Methyltransferase 3A; D004054:Diethylstilbestrol / Q000633:toxicity; D004822:Epididymis / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D015183:Restriction Mapping / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097584:DNA Methyltransferase 3B
D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D004054:Diethylstilbestrol; D000097584:DNA Methyltransferase 3B; C000715535:Dnmt3a protein, mouse; C000619381:Dnmt1 protein, mouse