title: An alternative method of deriving embryonic stem cell-like clones by aggregation of diploid cells with tetraploid embryos.
abstract: OBJECTIVE
  To assess whether embryonic stem (ES) cells could be derived from the aggregation of diploid cells with tetraploid embryos.
  
  
  METHODS
  Randomized, prospective study.
  
  
  METHODS
  University embryology and gamete biotechnology laboratory.
  
  
  METHODS
  F1 (C57BL6/DBA2) mice.
  
  
  METHODS
  Four- to eight-cell F1 tetraploid embryos were aggregated with 10 to 15 donor E14 ES cells.
  
  
  METHODS
  Embryogenesis and ES cell establishment.
  
  
  RESULTS
  No difference (78% to 89%) in blastocyst formation was detected between the aggregated tetraploid and the control diploid embryos. In a total of 27 transfers, pregnancy was detected in three tetraploid (23.1%) and five diploid (35.7%) cases, and three live births developed from the aggregated tetraploid embryos. The tetraploid blastocysts without aggregation were plated, but no ES cell-like colony was formed. Six of eight aggregated blastocysts derived well-proliferated colonies, which were positive for anti-stage-specific embryonic antigen (SSEA)-1 antibody, Oct-4, and alkaline phosphatase. The microsatellite assay confirmed the homogenous makeup among the donor E14 cells and live-birth and ES-like cells derived from the E14-aggregated, tetraploid embryo.
  
  
  CONCLUSIONS
  The aggregation of pluripotent diploid cells with tetraploid embryos yielded live births and ES-like cells that were homogenous to the donor diploid cells.
authors.affiliation: Department of Food and Animal Biotechnology, Seoul National University, Seoul, South Korea.
authors.forename: Meeyoung
authors.initials: M
authors.lastname: Cho
authors.forename: Mi
authors.initials: M
authors.lastname: Jang
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Lee
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Han
authors.forename: Jeong Mook
authors.initials: JM
authors.lastname: Lim
mesh_terms: D000818:Animals; D002449:Cell Aggregation / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology* / Q000502:physiology; D019976:Cloning, Organism / Q000379:methods*; D004171:Diploidy; D004622:Embryo, Mammalian / Q000166:cytology*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000502:physiology; D011123:Polyploidy; D023822:Tissue Engineering / Q000379:methods