title: Inactivated Sendai-virus-mediated fusion improves early development of cloned bovine embryos by avoiding endoplasmic-reticulum-stress-associated apoptosis.
abstract: Somatic cell nuclear transfer (SCNT) is a powerful tool, not only for producing cloned animals, but also in revealing various early developmental events. However, relatively little is known regarding the biological events and underlying mechanism(s) directly associated with early development of SCNT embryos. Here, we show that production of high-quality bovine SCNT blastocysts is dependent on the method used for fusion and the associated reduction in endoplasmic reticulum (ER) stress. During fusion between the donor cell and the enucleated oocyte, electrofusion triggers spontaneous oocyte activation, accompanied by an increase in intracellular Ca(2+) and improper nuclear remodelling. These events can be greatly reduced by the use of Sendai virus (SV)-mediated fusion. Moreover, SV-SCNT improves the blastulation rate and blastocyst quality, defined by the number and ratio of inner cell mass and trophectoderm cells in each blastocyst, in comparison with electrofusion-mediated SCNT (E-SCNT). Interestingly, expression of ER-stress-associated genes and blastomere apoptosis were significantly increased in E-SCNT embryos. These increases could be reversed by inhibition of ER stress or by using the SV-mediated fusion method. Collectively, these results indicate that SV-mediated fusion improves the developmental competence and quality of SCNT blastocysts, by reducing ER-stress-associated apoptosis.
authors.affiliation: National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk 363-883, Republic of Korea.
authors.forename: Bong-Seok
authors.initials: BS
authors.lastname: Song
authors.forename: Ji-Su
authors.initials: JS
authors.lastname: Kim
authors.forename: Seung-Bin
authors.initials: SB
authors.lastname: Yoon
authors.forename: Kyu-Sun
authors.initials: KS
authors.lastname: Lee
authors.forename: Deog-Bon
authors.initials: DB
authors.lastname: Koo
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Lee
authors.forename: Young-Kug
authors.initials: YK
authors.lastname: Choo
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Huh
authors.forename: Sang-Rae
authors.initials: SR
authors.lastname: Lee
authors.forename: Sun-Uk
authors.initials: SU
authors.lastname: Kim
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Hwan Mook
authors.initials: HM
authors.lastname: Kim
authors.forename: Kyu-Tae
authors.initials: KT
authors.lastname: Chang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001947:Breeding / Q000379:methods; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D019976:Cloning, Organism / Q000379:methods / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000196:embryology*; D059865:Endoplasmic Reticulum Stress / Q000502:physiology; D005307:Fertilization in Vitro / Q000379:methods / Q000662:veterinary*; D020287:In Situ Nick-End Labeling; D008856:Microscopy, Fluorescence; D053652:Nuclear Transfer Techniques / Q000662:veterinary*; D060888:Real-Time Polymerase Chain Reaction; D014760:Viral Fusion Proteins / Q000378:metabolism*
chemical_list: D014760:Viral Fusion Proteins; D002118:Calcium