title: Viable calves produced by somatic cell nuclear transfer using meiotic-blocked oocytes.
abstract: Somatic cell nuclear transfer (SCNT) has had an enormous impact on our understanding of biology and remains a unique tool for multiplying valuable laboratory and domestic animals. However, the complexity of the procedure and its poor efficiency are factors that limit a wider application of SCNT. In this context, oocyte meiotic arrest is an important option to make SCNT more flexible and increase the number of cloned embryos produced. Herein, we show that the use of butyrolactone I in association with brain-derived neurotrophic factor (BDNF) to arrest the meiotic division for 24 h prior to in vitro maturation provides bovine (Bos indicus) oocytes capable of supporting development of blastocysts and full-term cloned calves at least as efficiently as nonarrested oocytes. Furthermore, the procedure resulted in cloned blastocysts with an 1.5- and twofold increase of POU5F1 and IFNT2 expression, respectively, which are well-known markers of embryonic viability. Mitochondrial DNA (mtDNA) copy number was diminished by prematuration in immature oocytes (718,585±34,775 vs. 595,579±31,922, respectively, control and treated groups) but was unchanged in mature oocytes (522,179±45,617 vs. 498,771±33,231) and blastocysts (816,627±40,235 vs. 765,332±51,104). To our knowledge, this is the first report of cloned offspring born to prematured oocytes, indicating that meiotic arrest could have significant implications for laboratories working with SCNT and in vitro embryo production.
authors: Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, São Paulo, Brazil. tiagodebem@yahoo.com.br
authors: Tiago H C
authors: TH
authors: De Bem
authors: Marcos R
authors: MR
authors: Chiaratti
authors: Raquel
authors: R
authors: Rochetti
authors: Fabiana F
authors: FF
authors: Bressan
authors: Juliano R
authors: JR
authors: Sangalli
authors: Moysés S
authors: MS
authors: Miranda
authors: Pedro R L
authors: PR
authors: Pires
authors: Kátia R L
authors: KR
authors: Schwartz
authors: Rafael V
authors: RV
authors: Sampaio
authors: Paulo
authors: P
authors: Fantinato-Neto
authors: José R V
authors: JR
authors: Pimentel
authors: Felipe
authors: F
authors: Perecin
authors: Lawrence C
authors: LC
authors: Smith
authors: Flávio V
authors: FV
authors: Meirelles
authors: Paulo R
authors: PR
authors: Adona
authors: Cláudia L V
authors: CL
authors: Leal
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D002417:Cattle; D019976:Cloning, Organism / Q000379:methods*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007370:Interferon Type I / Q000096:biosynthesis; D008540:Meiosis / Q000187:drug effects*; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000096:biosynthesis; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D007370:Interferon Type I; D050814:Octamer Transcription Factor-3; D011257:Pregnancy Proteins; D047428:Protein Kinase Inhibitors; C020947:interferon tau; C082868:butyrolactone I; D015107:4-Butyrolactone