Transfer of a Mouse Artificial Chromosome into Spermatogonial Stem Cells Generates Transchromosomic Mice

精子幹細胞を使った人工染色体導入マウスの作成 --新規ヒト疾患モデル動物作成・男性不妊症治療法開発に期待--. 京都大学プレスリリース. 2017-09-25.The introduction of megabase-sized large DNA fragments into the germline has been a difficult task. Although microcell-mediated chromosome transfer into mouse embryonic stem cells (ESCs) allows the production of transchromosomic mice, ESCs have unstable karyotypes and germline transmission is unreliable by chimera formation. As spermatogonial stem cells (SSCs) are the only stem cells in the germline, they represent an attractive target for germline modification. Here, we report successful transfer of a mouse artificial chromosome (MAC) into mouse germline stem cells (GSCs), cultured spermatogonia enriched for SSCs. MAC-transferred GSCs maintained the host karyotype and MAC more stably than ESCs, which have significant variation in chromosome number. Moreover, MAC-transferred GSCs produced transchromosomic mice following microinjection into the seminiferous tubules of infertile recipients. Successful transfer of MACs to GSCs overcomes the problems associated with ESC-mediated germline transmission and provides new possibilities in germline modification