Rats produced by interspecies spermatogonial transplantation in mice and in vitro microinsemination

*Department of Molecular Genetics and
^¶Horizontal Medical Research Organization, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan;
^§Department of Development and Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; and
^‡National Institute for Physiological Sciences, Okazaki, Aichi 444-8787, Japan

Edited by Ryuzo Yanagimachi, University of Hawaii, Honolulu, HI, and approved July 27, 2006 (received for review May 22, 2006)

Abstract

Spermatogonial transplantation has demonstrated a unique opportunity for studying spermatogenesis and provided an assay for spermatogonial stem cells. However, it has remained unknown whether germ cells that matured in a xenogeneic environment are functionally normal. In this investigation, we demonstrate the successful production of xenogeneic offspring by using spermatogonial transplantation. Rat spermatogonial stem cells were collected from immature testis and transplanted into the seminiferous tubules of busulfan-treated nude mouse testis. Using rat spermatids or spermatozoa that developed in xenogeneic surrogate mice, rat offspring were born from fresh and cryopreserved donor cells after microinsemination with rat oocytes. These offspring were fertile and had a normal imprinting pattern. The xenogeneic offspring production by interspecies germ cell transplantation and in vitro microinsemination will become a powerful tool in animal transgenesis and species conservation.

Footnotes

^†To whom correspondence should be addressed at:
Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
E-mail: tshinoha{at}virus.kyoto-u.ac.jp
Author contributions: T.S. designed research; T.S., M.K., J.L., S.C., M.K.-S., and M.H. performed research; T.S., M.T., J.L., N.N., and M.H. analyzed data; and T.S. and M.K.-S. wrote the paper.
Conflict of interest statement: No conflicts declared.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviation:

COBRA,

combined bisulfite restriction analysis