title: NLRP7 and KHDC3L, the two maternal-effect proteins responsible for recurrent hydatidiform moles, co-localize to the oocyte cytoskeleton.
abstract: OBJECTIVE
  What is the subcellular localization in human oocytes and preimplantation embryos, of the two maternal-effect proteins, NLRP7 and KHDC3L, responsible for recurrent hydatidiform moles (RHMs)?
  
  
  CONCLUSIONS
  NLRP7 and KHDC3L localize to the oocyte cytoskeleton and are polar and absent from the cell-to-cell contact region in early preimplantation embryos.
  
  
  BACKGROUND
  NLRP7 and KHDC3L expression has been described at the RNA level in some stages of human oocytes and preimplantation embryos and at the protein level by immunohistochemistry in human and bovine ovaries. NLRP7 and KHDC3L co-localize to the microtubule organizing center and/or the Golgi apparatus in human hematopoietic cells.
  
  
  METHODS
  A total of 164 spare human oocytes and embryos from patients undergoing in vitro fertilization were used.
  
  
  METHODS
  Oocytes and early cleavage-stage embryos were fixed, immunostained with NLRP7 and/or KHDC3L antibodies, and analyzed using high-resolution confocal immunofluorescence and electron microscopies.
  
  
  RESULTS
  NLRP7 and KHDC3L localize to the cytoskeleton and are predominant at the cortical region in growing oocytes. After the first cellular division, these two maternal-effect proteins become asymmetrically confined to the outer cortical region and excluded from the cell-to-cell contact region until the blastocyst stage where NLRP7 and KHDC3L homogeneously redistribute to the cytoplasm and the nucleus, respectively.
  
  
  CONCLUSIONS
  We could not analyze fresh human oocytes and embryos. The analyzed materials were donated by patients undergoing assisted reproductive technologies and released for research 1-3 days after their collection and the transfer of embryos to the patients.
  
  
  CONCLUSIONS
  Our study is the first comprehensive and high-resolution localization of the only two known maternal-effect proteins, NLRP7 and KHDC3L, in human oocytes and preimplantation embryos. Our data contribute to a better understanding of the roles of these two proteins in the integrity of the oocytes, post-zygotic divisions, and cell-lineage differentiation.
  
  
  BACKGROUND
  This work was supported by the Canadian Institute of Health Research (86546 to R.S.); E.A. was supported by fellowships from the Research Institute of the McGill University Health Centre and a CREATE award from the Réseau Québécois en Reproduction. All authors declare no conflict of interest.
authors.affiliation: Department of Human Genetics, McGill University Health Center, Montreal, QC, Canada Department of Obstetrics and Gynecology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Elie
authors.initials: E
authors.lastname: Akoury
authors.affiliation: Department of Obstetrics and Gynecology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Obstetrics and Gynecology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Asangla
authors.initials: A
authors.lastname: Ao
authors.affiliation: Department of Human Genetics, McGill University Health Center, Montreal, QC, Canada Department of Obstetrics and Gynecology, McGill University Health Center, Montreal, QC, Canada rima.slim@muhc.mcgill.ca.
authors.forename: Rima
authors.initials: R
authors.lastname: Slim
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D001755:Blastocyst / Q000378:metabolism*; D016764:Cell Polarity; D003599:Cytoskeleton / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000235:genetics*; D009865:Oocytes / Q000378:metabolism*; D011247:Pregnancy; D011506:Proteins / Q000032:analysis* / Q000378:metabolism / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C568062:KHDC3L protein, human; C502448:NLRP7 protein, human; D011506:Proteins
keywords: KHDC3L; NLRP7; oocyte cortex; oocyte cytoskeleton; recurrent hydatidiform mole