title: Spindlin 1 is essential for metaphase II stage maintenance and chromosomal stability in porcine oocytes.
abstract: What is the function of Spindlin 1 (Spin1) in metaphase II stage oocytes in pigs?
  
  
  
  Depletion of Spin1 induces spontaneous oocyte activation and overexpression of Spin1 causes multinuclear formation through induction of DNA damage in porcine oocytes.
  
  
  
  Little is known about the function of Spin1 in oocytes and embryos. In mouse oocytes, Spin1 is specifically expressed during gametogenesis and is essential for meiotic resumption. In somatic cells, Spin1 promotes cancer cell proliferation and activates WNT/T-cell factor signaling.
  
  
  
  After knockdown (KD) or overexpression of Spin1 in porcine MII-stage oocytes, MII maintenance was checked following additional culture for 24 h. Investigated parthenotes were cultured up to the four cell (72 h) or blastocyst (7 days) stages.
  
  
  
  Spin1 was knocked down in porcine oocytes and embryos via microinjection of pig Spin1-targeting siRNA. For Spin1 overexpression, porcine Spin1-eGFP cRNA was generated. Additionally, for rescue experiments, cRNA encoding siRNA-resistant mouse Spin1 was added to the pig Spin1-targeting siRNA. For the overexpression and rescue experiments, microinjection and culture were performed using the same methods as the KD experiments.
  
  
  
  KD of Spin1 in MII-stage porcine oocytes reduced metaphase-promoting factor and mitogen-activated protein kinase activities, resulting in spontaneous pronuclear formation without calcium activation. However, the DNA damage response was triggered by Spin1 overexpression, generating the checkpoint protein γH2A.X. Furthermore, Spin1 overexpression blocked metaphase-anaphase transition and led to multinucleation in oocytes and embryos.
  
  
  
  None.
  
  
  
  This study is based on in vitro investigations with abnormal expression levels of Spin1. This may or may not accurately reflect the situation in vivo.
  
  
  
  Spin1 is essential to maintain MII arrest, but a high level of Spin1 induces DNA damage in oocytes and embryos. Thus, a system to accurately regulate Spin1 expression operates in porcine MII-stage oocytes and embryos.
  
  
  
  This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2015R1D1A1A01057629). The authors declare no competing financial interests.
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Choi
authors.affiliation: Division of Animal Biotechnology, National Institute of Animal Science, Rural Development Administration, Jeonju 55536, Republic of Korea.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liang
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Zi-Li
authors.initials: ZL
authors.lastname: Lin
authors.affiliation: Department of Animal Science, Yanbian University, Yanji, Jilin 133000, P.R. China.
authors.forename: Ying-Hua
authors.initials: YH
authors.lastname: Li
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Jo
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Nam-Hyung
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Department of Animal Science, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
authors.forename: Xiang-Shun
authors.initials: XS
authors.lastname: Cui
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D043171:Chromosomal Instability; D004249:DNA Damage; D004622:Embryo, Mammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008677:Metaphase; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine
chemical_list: D018797:Cell Cycle Proteins; D006657:Histones; D008869:Microtubule-Associated Proteins; D010750:Phosphoproteins; D034741:RNA, Small Interfering; C104434:spindlin; D049452:Green Fluorescent Proteins; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium
keywords: DNA damage; Spindlin 1; metaphase II stage maintenance; multinuclear formation; oocyte