Production of knockout mice by gene targeting in multipotent germline stem cells.
Spermatogonial stem cells can convert into embryonic stem (ES) cell-like multipotent germline stem (mGS) cells in vitro and produce germline chimeras by blastocyst microinjection. Although homologous recombination was previously demonstrated in mGS cells, spermatogenesis was not found in chimeras, suggesting that they are not competent for germline modification. Here we conducted detailed analysis of chimeric animals to determine whether mGS cells retain germline potential after genetic manipulation. Spermatozoa that were deficient in the occludin gene could be recovered from animals that were chimeric with mGS cells that underwent homologous recombination. The phenotypes of the occludin knockout (KO) mice were similar to those reported for KO mice produced using ES cells, and the animals showed growth retardation, gastritis and male infertility. Furthermore, we found that heterozygous mGS cells acquire two copies of the G418-resistant genes and become homozygous for the targeted allele by culturing at high concentrations of G418. Cytogenetic analysis showed that the aneuploid mGS cells observed during genetic manipulation were trisomic for chromosome 8 or 11, which is a common chromosomal abnormality in ES cells. Thus, mGS cells can be used to produce KO animals, and this novel method of germline manipulation may prove useful in diverse mammalian species.
Takehashi
Masanori
M
Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
Kanatsu-Shinohara
Mito
M
Miki
Hiromi
H
Lee
Jiyoung
J
Kazuki
Yasuhiro
Y
Inoue
Kimiko
K
Ogonuki
Narumi
N
Toyokuni
Shinya
S
Oshimura
Mitsuo
M
Ogura
Atsuo
A
Shinohara
Takashi
T
D000818:Animals; D002678:Chimera; D005260:Female; D005298:Fertility; D018390:Gene Targeting / Q000379:methods*; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism*; D006720:Homozygote; D007314:Insemination; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency; D051379:Mice; D018345:Mice, Knockout; D039902:Multipotent Stem Cells / Q000166:cytology* / Q000378:metabolism*; D062793:Occludin; D010375:Pedigree; D010641:Phenotype; D013091:Spermatogenesis; D013094:Spermatozoa / Q000378:metabolism; D013737:Testis / Q000378:metabolism
D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse