Although spermatogonial stem cells (SSCs) are committed to spermatogenesis, they may also convert to an embryonic stem cell-like pluripotent state at a low frequency. Because changes in DNA methylation patterns are associated with this conversion, we examined the effect of manipulating DNA methyltransferase (Dnmt) expression on the fate of cultured SSCs, germline stem (GS) cells. Dnmt1 knockdown induced apoptosis in GS cells, which was attenuated by the loss of Trp53. In contrast, GS cells proliferated normally in vitro after Dnmt3a/Dnmt3b ablation or during Dnmt3l overexpression. However, Dnmt3a/Dnmt3b double-mutant cells showed hypomethylation in the SineB1 repetitive sequence, and Dnmt3l-overexpressing cells showed hypermethylation in major and minor satellite sequences; neither cell type formed teratomas and completed spermatogenesis following transplantation into the seminiferous tubules. Although genetic manipulation did not increase the conversion of GS cells to a pluripotent state, these results underscore the important role of DNMTs in survival and spermatogenic differentiation in SSCs.
How to translate text using browser tools
18 February 2009
Abnormal DNA Methyltransferase Expression in Mouse Germline Stem Cells Results in Spermatogenic Defects
Seiji Takashima,
Masanori Takehashi,
Jiyoung Lee,
Shinichiro Chuma,
Masaki Okano,
Kenichiro Hata,
Isao Suetake,
Norio Nakatsuji,
Hiroyuki Miyoshi,
Shoji Tajima,
Yoriko Tanaka,
Shinya Toyokuni,
Hiroyuki Sasaki,
Mito Kanatsu-Shinohara,
Takashi Shinohara
ACCESS THE FULL ARTICLE
Biology of Reproduction
Vol. 81 • No. 1
July 2009
Vol. 81 • No. 1
July 2009
Apoptosis
developmental biology
meiosis
spermatogenesis
testis
