DNA methylation and gene expression dynamics during spermatogonial stem cell differentiation in the early postnatal mouse testis.
BACKGROUND
In the male germline, neonatal prospermatogonia give rise to spermatogonia, which include stem cell population (undifferentiated spermatogonia) that supports continuous spermatogenesis in adults. Although the levels of DNA methyltransferases change dynamically in the neonatal and early postnatal male germ cells, detailed genome-wide DNA methylation profiles of these cells during the stem cell formation and differentiation have not been reported.


RESULTS
To understand the regulation of spermatogonial stem cell formation and differentiation, we examined the DNA methylation and gene expression dynamics of male mouse germ cells at the critical stages: neonatal prospermatogonia, and early postntal (day 7) undifferentiated and differentiating spermatogonia. We found large partially methylated domains similar to those found in cancer cells and placenta in all these germ cells, and high levels of non-CG methylation and 5-hydroxymethylcytosines in neonatal prospermatogonia. Although the global CG methylation levels were stable in early postnatal male germ cells, and despite the reported scarcity of differential methylation in the adult spermatogonial stem cells, we identified many regions showing stage-specific differential methylation in and around genes important for stem cell function and spermatogenesis. These regions contained binding sites for specific transcription factors including the SOX family members.


CONCLUSIONS
Our findings show a distinctive and dynamic regulation of DNA methylation during spermatogonial stem cell formation and differentiation in the neonatal and early postnatal testes. Furthermore, we revealed a unique accumulation and distribution of non-CG methylation and 5hmC marks in neonatal prospermatogonia. These findings contrast with the reported scarcity of differential methylation in adult spermatogonial stem cell differentiation and represent a unique phase of male germ cell development.
Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.|Research Institute for Disease of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
Naoki
N
Kubo
Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
Hidehiro
H
Toh
Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
Kenjiro
K
Shirane
Department of Histology and Cell Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan.
Takayuki
T
Shirakawa
NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, 156-8502, Japan.
Hisato
H
Kobayashi
Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
Tetsuya
T
Sato
Department of Histology and Cell Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan.
Hidetoshi
H
Sone
Department of Histology and Cell Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan.
Yasuyuki
Y
Sato
Department of Histology and Cell Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan.
Shin-ichi
S
Tomizawa
Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, 236-0004, Japan.
Yoshinori
Y
Tsurusaki
Division of Genomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
Hiroki
H
Shibata
Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, 236-0004, Japan.
Hirotomo
H
Saitsu
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba, 277-8568, Japan.
Yutaka
Y
Suzuki
Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, 236-0004, Japan.
Naomichi
N
Matsumoto
Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan.
Mikita
M
Suyama
NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, 156-8502, Japan.|Department of BioScience, Tokyo University of Agriculture, Tokyo, 156-8502, Japan.
Tomohiro
T
Kono
Department of Histology and Cell Biology, Yokohama City University School of Medicine, Yokohama, 236-0004, Japan.
Kazuyuki
K
Ohbo
Division of Epigenomics and Development, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan. hsasaki@bioreg.kyushu-u.ac.jp.
Hiroyuki
H
Sasaki
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D019175:DNA Methylation; D020869:Gene Expression Profiling / Q000379:methods*; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D013091:Spermatogenesis; D013093:Spermatogonia / Q000166:cytology* / Q000502:physiology; D013234:Stem Cells / Q000502:physiology*