title: Production of cloned pigs by whole-cell intracytoplasmic microinjection.
abstract: Cloning by somatic cell nuclear transfer has been successfully achieved by both fusing of a donor cell with and injecting an isolated donor cell nucleus into an enucleated oocyte. However, each of the above methods involves extended manipulation of either the oocytes (fusion) or the donor cells (nucleus isolation). Additionally, cloning efficiency can be reduced by low fusion rate of the cell fusion method, and specialized micromanipulation equipment and exacting nucleus isolation techniques are required for the nucleus injection method. Here we report a whole-cell injection technique for nuclear transfer in pigs and the production of cloned piglets with comparable, if not higher, efficiency than the other two nuclear transfer procedures. First, we tested the feasibility of this technique with three types of frequently used donor cells (cumulus, mural granulosa, and fibroblasts) and obtained the optimal nuclear reprogramming conditions for these cells. We further improved our protocol by avoiding ultraviolet exposure during enucleation and achieved a 37% blastocyst rate. We then conducted whole-cell injection using skin fibroblasts from the ear of a sow transgenic for two genes, the porcine lactoferrin and the human factor IX, and produced four live-born cloned transgenic piglets from three recipients. The present study demonstrated the applicability of producing normal, cloned piglets by the simple and less labor-intensive whole-cell intracytoplasmic injection.
authors.affiliation: Department of Animal Science and Connecticut Center for Regenerative Biology, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Jang-Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Shin-Chih
authors.initials: SC
authors.lastname: Wu
authors.forename: X Cindy
authors.initials: XC
authors.lastname: Tian
authors.forename: Michele
authors.initials: M
authors.lastname: Barber
authors.forename: Thomas
authors.initials: T
authors.lastname: Hoagland
authors.forename: John
authors.initials: J
authors.lastname: Riesen
authors.forename: Kun-Hsiung
authors.initials: KH
authors.lastname: Lee
authors.forename: Ching-Fu
authors.initials: CF
authors.lastname: Tu
authors.forename: Winston T K
authors.initials: WT
authors.lastname: Cheng
authors.forename: Xiangzhong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D002459:Cell Fusion / Q000379:methods; D002467:Cell Nucleus / Q000235:genetics; D019976:Cloning, Organism / Q000379:methods*; D003593:Cytoplasm / Q000378:metabolism / Q000637:transplantation; D004624:Embryo Transfer; D005347:Fibroblasts / Q000166:cytology*; D008845:Microinjections; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000166:cytology*; D013552:Swine / Q000235:genetics*