Document Detail

Early zygotes are suitable recipients for bovine somatic nuclear transfer and result in cloned offspring.
MedLine Citation:
PMID:  17127744     Owner:  NLM     Status:  MEDLINE    
Cloning by somatic cell nuclear transfer (SCNT) subverts sperm-mediated fertilization that normally leads to physiological activation of the oocyte. Therefore, artificial activation is required and it is presently unclear what developmental consequences this has. In this study, we aimed to improve cattle cloning efficiency by utilizing a more physiological method of activating SCNT reconstructs. We carried out in vitro fertilization (IVF) of zona-intact bovine oocytes before SCNT. We removed the zona pellucida 4 h after insemination, stained the fertilized eggs with Hoechst 33342 and mechanically removed both male and female chromatin. The enucleated pre-activated cytoplasts were fused with male adult ear skin fibroblasts ("IVF-NT" group). Chemically activated SCNT embryos, produced according to our standard operating procedure for zona-free SCNT, served as controls. After 7 days, in vitro development to blastocysts of morphological grade 1-3 or grade 1-2 was very similar in both groups (39 vs 40% and 20 vs 21% respectively). However, post-implantation development was improved after sperm-mediated activation. Across four replicate runs, pregnancy establishment at day 35 was significantly higher for IVF-NT than for control SCNT embryos (30/49 = 61 vs 17/41 = 42% respectively; P < 0.05). Development into calves at term or weaning was also higher in the IVF-NT group compared with control SCNT (9/49 = 18 vs 3/41 = 7% and 6/49 = 12 vs 3/41 = 7%; P = 0.11 and 0.34 respectively).
Anita Schurmann; David N Wells; Björn Oback
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Reproduction (Cambridge, England)     Volume:  132     ISSN:  1470-1626     ISO Abbreviation:  Reproduction     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2006-11-27     Completed Date:  2007-06-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100966036     Medline TA:  Reproduction     Country:  England    
Other Details:
Languages:  eng     Pagination:  839-48     Citation Subset:  IM    
AgResearch Ltd, Ruakura Research Centre, Reproductive Technologies, East Street, Hamilton, New Zealand.
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MeSH Terms
Adenine / analogs & derivatives,  pharmacology
Cells, Cultured
Cloning, Organism / methods,  veterinary*
Embryo Transfer
Fertilization in Vitro
Ionomycin / pharmacology
Ionophores / pharmacology
Nuclear Transfer Techniques / veterinary*
Pregnancy Outcome
Protein Kinase Inhibitors / pharmacology
Reg. No./Substance:
0/Ionophores; 0/Protein Kinase Inhibitors; 56092-81-0/Ionomycin; 73-24-5/Adenine; 938-55-6/N(6),N(6)-dimethyladenine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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