Genome activation and developmental block in bovine embryos.
Anim Reprod Sci
; 82-83: 13-20, 2004 Jul.
Article
in En
| MEDLINE
| ID: mdl-15271440
ABSTRACT
The ultimate goal of in vitro embryo culture systems is to perfectly mimic the condition of oocyte maturation, fertilization and embryo development. These systems are far more complex than standard in vitro cell culture because of the various environments through which the gametes and embryos pass during in vivo development. Improvement of the medium and other culture conditions has allowed for full development of a percentage of the fertilized oocytes but the great majority of bovine zygotes stop developing within a few cell cycles after initiating cleavage. This developmental block arises in the bovine embryo at the eight-cell-stage and is likely correlated with the cytoplasmic quality of the oocyte. Oocytes harbor all mRNAs and proteins needed to reach the fourth or fifth cell cycle, however, embryos that fail to transcribe their own genome fail to further develop. In this article, we review some of the advances in developmental block knowledge and describe a possible role of active embryo transcription that drives incompetent embryos to block and death.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Cattle
/
Gene Expression Regulation
/
Embryonic and Fetal Development
Limits:
Animals
Language:
En
Journal:
Anim Reprod Sci
Year:
2004
Document type:
Article
Affiliation country:
Brazil