title: Establishment of germline-competent embryonic stem cell lines from the MSM/Ms strain.
abstract: MSM/Ms is an inbred mouse strain established from the Japanese wild mouse, Mus musculus molossinus, which has been phylogenetically distinct from common laboratory mouse strains for about 1 million years. The nucleotide substitution rate between MSM/Ms and C57BL/6 is estimated to be 0.96%. MSM/Ms mice display unique characteristics not observed in the commonly used laboratory strains, including an extremely low incidence of tumor development, high locomotor activity, and resistance to high-fat-diet-induced diabetes. Thus, functional genomic analyses using MSM/Ms should provide a powerful tool for the identification of novel phenotypes and gene functions. We report here the derivation of germline-competent embryonic stem (ES) cell lines from MSM/Ms blastocysts, allowing genetic manipulation of the M. m. molossinus genome. Fifteen blastocysts were cultured in ES cell medium and three ES lines, Mol/MSM-1, -2, and -3, were established. They were tested for germline competency by aggregation with ICR morulae and germline chimeras were obtained from all three lines. We also injected Mol/MSM-1 ES cells into blastocysts of ICR or C57BL/6 x BDF1 mice and found that blastocyst injection resulted in a higher production rate of chimeric mice than did aggregation. Furthermore, Mol/MSM-1 subclones electroporated with a gene trap vector were also highly efficient at producing germline chimeras using C57BL/6 x BDF1 blastocyst injection. This Mol/MSM-1 ES line should provide an excellent new tool allowing the genetic manipulation of the MSM/Ms genome.
authors.affiliation: Department of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University, Honjo 2-2-1, Kumamoto, 860-0811, Japan. arakimi@gpo.kumamoto-u.ac.jp
authors.forename: Kimi
authors.initials: K
authors.lastname: Araki
authors.forename: Naoki
authors.initials: N
authors.lastname: Takeda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshiki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Obata
authors.forename: Naomi
authors.initials: N
authors.lastname: Nakagata
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shiroishi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Moriwaki
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yamamura
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000196:embryology; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D002678:Chimera / Q000196:embryology; D003433:Crosses, Genetic; D018274:Electroporation; D046149:Embryo Culture Techniques; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology*; D005260:Female; D005854:Germ Cells / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008815:Mice, Inbred Strains