title: Influence of intergeneric/interspecies mitochondrial injection; parthenogenetic development of bovine oocytes after injection of mitochondria derived from somatic cells.
abstract: Interspecies/intergeneric mitochondrial heteroplasmy can occur in interspecies/intergeneric hybrid embryos or following nuclear transfer. In the present study, intergeneric buffalo (Bubalus bubalis) mitochondria (WB-mt) or interspecies murine (Mus spretus) mitochondria (M-mt) were injected into bovine (Bos taurus) oocytes, and the subsequent embryonic development was characterized. Fibroblast mitochondria (WB-mt or M-mt) were microinjected into in vitro matured bovine oocytes followed by oocyte activation by a combination of electrical stimulation and 6-dimethylaminopurine treatment. After seven days of culture, embryo development was evaluated. The copy number of specific mtDNA populations (introduced and native mtDNA) from heteroplasmic oocytes was estimated using real-time PCR. The results illustrated that oocytes injected with either WB-mt or M-mt can develop to the blastocyst stage (20.6% and 19.6%). Cleavage division rates and development to the morula stage in oocytes injected with WB-mt were lower (76.2% and 45.9%, respectively) in comparison with uninjected oocytes (89.2% and 59.1%, respectively) (P<0.05). However, no differences were found in comparing M-mt injected oocytes and controls (P>0.05). An increase in bovine mtDNA copy number was observed at the expanded blastocyst stage of injected embryos (P<0.01), while the number of injected mtDNA was stable throughout development. This study demonstrates that interspecies/intergeneric mitochondrial injected bovine oocytes have the ability to develop to the blastocyst stage after parthenogenetic activation and that injected mtDNA was neither selectively destroyed nor enhanced through development. Moreover, injected intergeneric mitochondria had a demonstrated influence on bovine parthenogenetic development and mtDNA replication.
authors.affiliation: Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Ibaraki 305-0901, Japan. kumiko@affrc.go.jp
authors.forename: Kumiko
authors.initials: K
authors.lastname: Takeda
authors.forename: Kanokwan
authors.initials: K
authors.lastname: Srirattana
authors.forename: Kazutsugu
authors.initials: K
authors.lastname: Matsukawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Akagi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kaneda
authors.forename: Mariko
authors.initials: M
authors.lastname: Tasai
authors.forename: Keijiro
authors.initials: K
authors.lastname: Nirasawa
authors.forename: Carl A
authors.initials: CA
authors.lastname: Pinkert
authors.forename: Rangsun
authors.initials: R
authors.lastname: Parnpai
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D000818:Animals; D002020:Buffaloes; D002417:Cattle; D004272:DNA, Mitochondrial / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D018628:Gene Dosage; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D010312:Parthenogenesis / Q000502:physiology*; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial; C001020:N(6),N(6)-dimethyladenine; D000225:Adenine