Epigenetic marks by DNA methylation specific to stem, germ and somatic cells in mice.
BACKGROUND
DNA methylation is involved in many gene functions such as gene-silencing, X-inactivation, imprinting and stability of the gene. We recently found that some CpG islands had a tissue-dependent and differentially methylated region (T-DMR) in normal tissues, raising the possibility that there may be more CpG islands capable of differential methylation.


RESULTS
We investigated the genome-wide DNA methylation pattern of CpG islands by restriction landmark genomic scanning (RLGS) in mouse stem cells (ES, EG and trophoblast stem) before and after differentiation, and sperm as well as somatic tissues. A total of 247 spots out of 1500 (16%) showed differences in the appearance of their RLGS profiles, indicating that CpG islands having T-DMR were numerous and widespread. The methylation pattern was specific, and varied in a precise manner according to cell lineage, tissue type and during cell differentiation.


CONCLUSIONS
Genomic loci with altered methylation status seem to be more common than has hitherto been realized. The formation of DNA methylation patterns at CpG islands is one of the epigenetic events which underlies the production of various cell types in the body. These findings should have implications for the use of embryonic stem cells and cells derived from them therapeutically, and also for the cloning of animals by the transfer of somatic cell nuclei.
Shiota
Kunio
K
Laboratory of Cellular Biochemistry, Animal Resource Sciences/Veterinary Medical Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. ashiota@mail.ecc.u-tokyo.ac.jp
Kogo
Yasushi
Y
Ohgane
Jun
J
Imamura
Takuya
T
Urano
Atsushi
A
Nishino
Koichiro
K
Tanaka
Satoshi
S
Hattori
Naka
N
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D019070:Cell Lineage; D002478:Cells, Cultured; D018899:CpG Islands; D004247:DNA / Q000032:analysis; D019175:DNA Methylation; D005854:Germ Cells / Q000502:physiology*; D051379:Mice; D015183:Restriction Mapping / Q000379:methods; D013234:Stem Cells / Q000502:physiology*
D004247:DNA